If you lack fundamentals, than work on those. Build from the ground up. Doing a million hit fancy combo's aren't going to help if you can never land anything.
When I help people get into SF, I like to do matches with them, and force them to just use footsies and pokes, no jumping, no specials moves. It helps them find the range of all of their buttons, not just Fierce and Roundhouse. Jumping is usually suicide, try to do it as minimal as possible. I know Injustice is more lenient with jumping, but you need to know when and how to do it.
Since you've played Bison in SF4, try out Doomsday. Nice corner pressure, big reaching normal attacks, decent mobility, and his execution is minimal. People believe he is a purely gimmick character, and that can be very true fighting scrubs, or the majority of people online, but against anyone good, using Doomsday forces you to have great fundamentals, spacing and reads, Using gimmicks will get you killed.