EDIT: One tip? Can't pick. Sorry OP. Regardless, hope perhaps one of these is worth it.
Either be funny, insightful or at the very least interesting.
Be nice. Follow the rules.
Have empathy. If not, spare some sympathy.
Think of Reddit as an idea game, not a popularity contest. I've detailed the rules of the meta-game in a former question
...and his experience thus only reaffirms his belief that everyone else is the problem.
If there is anything to be learned from the sad story of Elliot Rodger, it’s that "everyone else” is never the problem.
It’s easy to think that way, and technology makes it even easier, as we fire off talking points and skip the responses and only read articles with which we already agree.
But if you want to make a difference, if you want to find a girlfriend or fight misogyny or stop gun violence or anything else, then this illusion
is not going to help you. When you want to shout your views to the world, ask yourself: how would someone who disagreed with me hear this? If the answer is “They would be angry,” or “They would ignore it,” then you are little different from Elliot acting “cocky and arrogant” at the party, setting himself up for a result that will confirm his righteous fury.
Do not take the easy way out and write off groups of people as unilaterally Good or Evil. Good and Evil exist within each one of us. Only a Sith deals in absolutes.