For me I think its a mix of luck(=genetics), sheer determination and lot of reading online on what works and what doesn't. Also find out how you can compliment the HRT if you choose to go that way, there's plethora of stuff to give you an edge. But I would say your young age is your best secret weapon into making the body of your dreams come true.
How cool is that, I gave you a first time on something. Take my word for it, your lips are perfect. Now just imagine how much more plump and full they will look like once you get your hormone levels fixed. I know mine have gotten prettier and definitely they look bigger than before. (One of the parts I've always liked about my body btw.)
The best advice I can give is to not get frustrated or hasty, the things you want will take years to happen, even at your age, but you certainly have a big advantage there, fantastic opportunity for anything, so don't waste it.
But I'm rambling again, more YOU as this is your intro. <3
EDIT:
Are you on Discord? There's a very nice server run by a certain member of this forum, I'm there too along with several familiar names around here, the chat is very active and its a nice bunch of people. Chime in if you want to discuss things in real time.
https://discord.com/channels/32461195772...7720350725