Check Small Examples
If you have a number theory question, on whether a certain property holds for some numbers, run a computer search to make sure that there are no trivial counter examples to your statement.
As Sarvesh says, If you're running any code pertaining to a question, please post the code as well, so that others can run it or modify it and obtain other patterns". This is extremely helpful because others may have higher computational power or have some hypothesis to test for which having the source code would be really helpful. Also, posting the code is an explicit demonstration of effort, unlike writing “I wrote some code and it spat out 3,17,1221 3 , 17 , 1221 , I don't see a pattern?”