Hey there, thanks for the nice comment!
As for drawing characters - I'd suggest getting used to observing the people around you, especially when out and about in the world. How they move, howw their proportions and bodies are structured, how they interact with their environment and vice versa. (obviously, I don't mean to say "stare at everyone for prolonged stretches of time", but that should be clear anyway). If you feel awkward studying irl people, that's fine. Movies and TV exist too. ^^
Personally I like to use a sketchbook to have a chronological overview of the things I've drawn, as well as note down things I noticed. I carry something to draw wherever I go.
As for Bionicle characters, it depends on what you want to do? If you want to lean in a set-like direction, make sure you either have the set around or look for images online so you have a reference to help you.
Stylization is a harder one to comment on. I'd say dare to try new things, and keep in mind that not everything will always work out, and that's okay! Using references also helps a lot. Say you want to draw a character that's associated with Plant Life, and you have the idea to add leaf textures somewhere in their armour. The illusion becomes a lot more believable if you look at images (or ideally, a real leaf ).
Personally I like to model the characters on the human form, so I just sketch that out first, then use the set to figure out the shapes for the armour. For a while I even used to draw the characters completely humanized/as humans - that wasn't quite popular ^^' but I liked it back then, so yea. Draw what you like, what you enjoy.
Figure out what inspires you, draw from that. Study it, too. Look at art you enjoy and figure out why - is it the poses? The stylization? The lighting? Try to analyze that and finally - don't forget to practise, but also to have fun!
... okay, this was a lot more than anticipated. I hope some of it was helpful.