Same old story bro...Make lots of funny meme comments on front page memes as well as memes in the latest stream...be funny and be respectful and people will start upvoting your comments and taking notice of the memes YOU make...it will not happen overnight but it doesn't take long if you keep at it...whatever you do, do not complain or attack other users...if there is one thing this community does NOT like, it's crybabies...there are ways of expressing your concerns without painting a target on your back...
Experiment submitting memes at different times of the day...sometimes I submit in the morning, sometimes I submit at night...in my experience, user template memes "sometimes" feature faster in the evening but not always...but it never hurts to try different things...You may have noticed that sometimes I'll submit memes of a certain theme(like funny street signs) for a few days, then I might switch to a different theme for awhile...I went through a Praying Mantis phase quite awhile back, but people got tired of that, so I quit doing that...just remember that just because you think something is funny doesn't mean the rest of Imgflip will...if you have any specific questions, I'll try to answer them...but I would start with the funny comments.
And I never allow myself to get sucked into Flame wars with childish people....that will hurt you more than anything...just ignore the haters and you will go far...Good luck.