Not sure if this is really a tips/ tricks thing, but it's just my LAME opinion that I wanna share
I stumbled on this fan art contest post from Webtoons and some or most of people's fan art entries that I saw are purely traced off or heavily referenced (same author's art style) of the author's artwork on her comics. There are some slight tweaks like probably changing the clothing/body but it's same exact traced heads of the characters literally right off from the comic.
This is my opinion by the way, you don't need to agree with it. I am sorry if this will come off as misunderstanding, as I can't sometimes explain my thoughts well.
If you're joining fan art contests like these or you just wanna make fan art of your favorite comics/ characters you gotta at least do them in your own art style (if you do have) , it would be more unique in my opinion. I am pretty sure the author would love to see more of their characters in a different perspective/ art style, orrr when you use the same art style as the author's make sure you do it differently and not copying off the exact same pose, angle and scene already existing from the comic. It reminds me like one of those children's art books were you try your best to copy / draw the same picture/drawing.
Pls don't even take off even a part of the author's artwork like simply tracing the character's head from the comic and just simply draw them with another outfit. PLS.
THIS is different from doing realistic art though, that's another story.
But this just mainly goes for a comic's fan art contest if you want higher chances of winning (in my opinion, I am not saying this is how the author would choose winners) Though I know not a lot of people have art as their forte or thing, but I respect anyone's choice on what they wanna do as long as it's legal, show proper credit (if they use someone else's work) and they would have fun.
Though If they are still beginners, or still children I would still let them enjoy their own thing (I mean we all experienced this stage, right) until they are old or mature enough to know why or remind them gently on which is more proper to do.
Sorry for the stupid ramble. Kill me pls