Sorry that I didn't answer you right away Omis, however if I was to tell everything, it would take ages for me to write it down for you. However, I will tell you the fundamentals though and try to limit my wording.
The thing you should learn how to do above all else is get your executions down, meaning to truly master your specials and attacks, so that they come out on call. Make it so that you can achieve success on your moves 99% of the time, not 75% or 80%, that's still too random.
Also know where your character's sweet's spots are, like for instance, I play Ryu right, and in SF:IV he has alot of sweet spots, like at full screen I'll be throwing out projectiles, at mid-range to outside of sweep range, I start to shoot less projectiles and more Ex-Hadou's and I start to get my footsie game going. Up close I will mixup, throw, or try to land ShoryukenxxFADC.
Understanding where your character dominates, and what tools best to use when your in that situation is a must. Again, this will require you to really know how to position your character, because I cannot emphasize this enough. You will go nowhere if you do not know how to position your character to dominate in SF:IV.
So this is what you should start out with...
- Learn your character's attacks and specials All of them, regardless if some are not as useful, learn them all, and make sure you can do it 99% of the time (you could never be 100% because we aren't perfect).
- Learn how to FADC, obviously this is a SF:IV thing, and if you don't know already FADC means Focus Attack Dash Cancel. Which you are basically canceling your FA into a dash right away, obviously this works better on certain characters more so then others, however this is a must.
- Once you have gotten these basics of moves/specials down, then you can start learning how to position your character on the stage and against your opponent. This is arguably going to be the hardest part, because learning how to position your character to dominate will require the most effort because you are utilizing all of your tools above and incorporating it into your gameplay, however once you get this down to at least a solid level, you'll become a much better player already.
Again, fundamentals are a must, knowing how to defend against attacks, knowing how to punishing, mastering all of your attacks/specials comes first before all of the "flashy combos" or big "damaging combos".
That's how I learned how to play Street Fighter back then, I learned the basics first, then from there, slowly went upward, so if you want to learn SF:IV, that's what you'll have to do if you want to become at least a solid player.
Hope this kinda helps, however if you need anything else, just let me know,
OWS