Look through the movelist. There are some Top 10 moves in some Soul Arenas iirc. They can answer you questions in the Q&A. However, your skills won't develop if you always win so keep that in mind
Watch a vid, or watch someone play that character and make notes of things that work well. Then, pick those moves out and develop a way to set them up, all while making tactical adjustments. If you don't want to be completely obliterated your first time online with that char, try versus, or start off with more inexperienced players to get move timing down.
After that, take he or she out for a test drive against someone skilled at who they use and someone who may be skilled at dealing with your match up, which will help you formulate your game plan, learning your own weaknesses, as well as theirs. From then on, it's just a matter of getting comfortable with your new skin. Maybe that'll help?
Lol, I kinda got carried away, but that's my take on the technical/mental balance of learning a new character. 'Tis not a method for the world, but you can try it out for yourself, if it's not what you've already been doing (>^.^)>