I am trying to step to the next level from student to amateur web developer, and I would like to make sure I am not making any web-development no-no's, that's all. What caused me to want to ask SO this question is that I had to make some tweaks to make my responsive design work.
For instance, I had to make a lot of my positions "absolute" and had to do some hacking in my HTML, making a different nav bar if it's mobile, desktop or tablet (you'll see I haven't done anything with tablet) design. I'm also pretty new to jQuery, although I'm a programmer so I think that code is okay, but I'll post it anyways. Some other stuff as well, would really appreciate ANY feedback, and I really want some good criticism so I can become better.
HTML
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<script>
$(document).ready(function () {
        $('nav').hide();
        $('.maDown').hide();
    $('.assignmentsDown').click(function() {
        $('nav.aDown').slideDown(2000);
        if($('.wDown').is(":visible"))
        {
            $('nav.wDown').slideToggle(300);
        }
        if($('.pDown').is(":visible"))
        {
            $('nav.pDown').slideToggle(300);
        }
        $('nav.aDown').slideDown(2000);
    });
        $('.MassignmentsDown').click(function() {
        $('.maDown').show();
    });
    $('.writingDown').click(function() {
        $('nav.wDown').slideDown(2000);
        if($('.aDown').is(":visible"))
        {
            $('nav.aDown').slideToggle(300);
        }
        if($('.pDown').is(":visible"))
        {
            $('nav.pDown').slideToggle(300);
        }
    });
    $('.presentationDown').click(function() {
        $('nav.pDown').slideDown(2000);
        if($('.wDown').is(":visible"))
        {
            $('nav.wDown').slideToggle(300);
        }
        if($('.aDown').is(":visible"))
        {
            $('nav.aDown').slideToggle(300);
        }
    });
}); //closes ready
</script>
</head>
    <figure>
        <img src="downwardmonkey.png" alt="down" class="head">
    </figure>
<body>
    <div id="navContainer">
            <h1 class="mainT"> Al Gore Rhythm Labs </h1>
            <h2 class="subT"> Chicago, IL </h2>
            <div class="topNav">
                <ul>
                    <li> <a href="#" class="assignmentsDown"> Assignments </a></li>
                    <li> <a href="#" class="writingDown"> Writings </a> </li>
                    <li> <a href="#" class="presentationDown"> Presentations </a></li>
                </ul>
            </div>
            <div class="mNav">
                    <p> <a href="#" class="MassignmentsDown"> Assignments |</a></p>
                    <p> <a href="#" class="MwritingDown"> Writings |</a> </p>
                    <p> <a href="#" class="MpresentationDown"> Presentations </a></p>
            </div>
            <div class="maDown">
                <ul>
                    <li class="assignments"><a href="origindex.html" class="a"> First Class Page (A1) </a></li>
                    <li class="assignments"><a href="#" class="a"> Responsive Class Page (A2) </a></li>
                    <li class="assignments"><a href="A3.html" class="a"> CSS Engagement (A3) </a></li>
                    <li class="assignments"><a href="A4.html" class="a"> Transitions and Animations (A4) </a></li>
                    <li class="assignments"><a href="A5.php" class="a"> jQuery (A5) </a></li>
                    <li class="assignments"><a href="A6.html" class="a"> jQuery Usability (A6) </a></li>
                    <li class="assignments"><a href="A7.html" class="a"> HTML5 Form (A7) </a></li>
                </ul>
            </div>
    </div>
    <nav class="aDown">
        <ul>
            <li class="assignments"><a href="origindex.html" class="a"> First Class Page (A1) </a></li>
            <li class="assignments"><a href="#" class="a"> Responsive Class Page (A2) </a></li>
            <li class="assignments"><a href="A3.html" class="a"> CSS Engagement (A3) </a></li>
            <li class="assignments"><a href="A4.html" class="a"> Transitions and Animations (A4) </a></li>
            <li class="assignments"><a href="A5.php" class="a"> jQuery (A5) </a></li>
            <li class="assignments"><a href="A6.html" class="a"> jQuery Usability (A6) </a></li>
            <li class="assignments"><a href="A7.html" class="a"> HTML5 Form (A7) </a></li>
        </ul>
    </nav>
    <nav class="wDown">
        <ul>
            <li class="writings"><a href="#" class="Writing1.html"> How HTML Will Kill The Native App (W1) </a></li>
            <li class="writings"><a href="#" class="Writing2.html"> Ubiquitous Computing (W2) </a></li>
            <li class="writings"><a href="#" class="Writing3.html"> Re-examining Interactivity (W3) </a></li>
        </ul>
    </nav>
    <nav class="pDown">
        <ul>
            <li class="presentations"><a href="PresOne.html" class="p"> Interactive Interests (P1) </a></li>
            <li class="presentations"><a href="P2.html" class="p"> Experimental Interactive Artifacts (P2) </a></li>
            <li class="presentations"><a href="P3.html" class="p"> Research Assets (P3) </a></li>
        </ul>
    </nav>
    </body>
    <figure>
        <div class="grassImageDiv"></div>
   </figure>
    <footer> 
        <p><a href="http://www.jdmdev.net"> Jordan Max 2014 </a></p>
    </footer>
</html>
CSS3
/********************* DEFAULT QUERIES *********************/
body
{
    background-image: url("bg.gif");
}
/******************** MOBILE QUERIES ********************/
@media all and (max-width: 600px) {
a.assignmentsDown, a.writingDown, a.presentationDown, div.topNav
{
    display: none;
}
h1, h2
{
    text-align: center;
    width: 100%;
    color: #9aa49a;
}
h1.mainT
{
    font-family: 'Montserrat', sans-serif;
    font-size: 1.5em;
}
h2.subT
{
    font-family: 'Open Sans Condensed', sans-serif;
    margin-top: -17px;
}
div#navContainer
{
    background: #FCFCFC;
    height: 80px;
    width: 100%;
}
img.head
{
    display: none;
}
a
{
    color: #8B8B83;
    text-decoration: none;
}
footer
{
    color: #9aa49a;
    font-family: 'Montserrat', sans-serif;
    background-color: #FCFCFC;
    width: 100%;
    height: 38px;
    font-size: .85em;
    text-align: center;
    padding: 5px;
    position: absolute;
    bottom: 0;
}
.grassImageDiv
{
    display: inline-block;
    background-image: url("grass3.png");
    position: absolute;
    height: 107px;
    width: 108%;
    bottom: 44px;
    margin-left:-61px;
    overflow-x: hidden;
}
.mNav
{
    text-align: center;
    background-color: #FCFCFC;
    box-shadow: 10px 10px 5px #888888;
    top: 96px;
    width: 100%;
    position: absolute;
}
div.mNav>p
{
    font-family: 'Open Sans Condensed', sans-serif;
    font-size: 1.2em;
    height: 70%;
    list-style-type: none;
    display: inline;
}
ul li.assignments, li.writings, li.presentations
{
    line-height: 250%;
    list-style-type: none;
    font-family: 'Montserrat', sans-serif;
}
div.maDown
{
    background: #FCFCFC;
    width: 300px;
    box-shadow: 2px 3px 10px #333;
}
} /******************** end media query ********************/
/******************** TABLET QUERIES ********************/
@media all and (min-width: 600px) {
aside
{
}
} /******************** end media query ********************/
/******************** Desktop Queries ********************/
@media all and (min-width: 1240px){
}
/******************** Large Desktop Queries ********************/
@media all and (min-width: 1240px){
div.mNav
{
    display: none;
}
div.maDown
{
display: none;
}
h1
{
}
h2
{
    margin-top: -40px;
    margin-left: 120px;
}
h1.mainT
{
    width: 590px;
    font-family: 'Montserrat', sans-serif;
    margin-left: 10px;
    font-size: 2.5em;
}
h2.subT
{
    width: 130px;
    font-family: 'Open Sans Condensed', sans-serif;
}
nav
{
    font-family: 'Open Sans Condensed', sans-serif;
    font-size: 1.2em;
    width: 500;
    height: 70%;
    background-color: #FCFCFC;
    padding: 5px;
    margin: 10px auto 30px 42%;
    box-shadow: 2px 3px 10px #333;
    position: fixed;
    margin-left: 42%;
    top: 15%;
    left: -100px;
}
div.topNav>ul>li
{
    display: inline-block;
    font-family: 'Open Sans Condensed', sans-serif;
    font-size: 1.2em;
    list-style-type: none;
}
div.topNav
{
    word-spacing: 75px;
    margin-top: -60px;
    margin-left: 650px;
}
a
{
    color: #8B8B83;
    text-decoration: none;
}
footer
{
    color: #9aa49a;
    font-family: 'Montserrat', sans-serif;
    background-color: #FCFCFC;
    width: 100%;
    font-size: .85em;
    position: fixed;
    left: 0px;
    bottom: 0px;
    text-align: center;
    z-index: 1;
}
div#navContainer
{
    height: 100px;
    background: #FCFCFC; /* grey99*/
    box-shadow: 2px 3px 5px #333;
    position: fixed;
    width:100%;
    z-index: 1;
}
ul li.assignments, li.writings, li.presentations
{
    width: 400px;
    line-height: 250%;
    margin-left: -25px;
    margin-right:27px;
    padding: 20px;
    list-style-type: none;
    font-family: 'Montserrat', sans-serif;
    text-align: center;
    z-index: 1;
}
div.temp
{
    z-index:1;
}
a:hover.a,:hover.w,:hover.p
{
    color: #C1CDC1;
}
figure img.head
{
    position: fixed;
    top:117px;
    margin-left: 58px;
}
p.clickHere
{
    position: fixed;
    top: 450px;
    left: 77%;
    font-family: 'Open Sans Condensed', sans-serif;
    font-size: 1.6em;
    color: #EDEFED;
}
.grassImageDiv
{
    display: inline-block;
    background-image: url("Grass2.png");
    width: 120%; 
    height: 216px;
    position: fixed;
    margin-left:-96px;
    bottom: 42px;
    z-index: -1;
}
/******************** end media query ********************/