Who are some of your mains, if you have any? If FADCing is hard for you, maybe use a character that doesn’t depend on it too much. Some characters don’t really need it… while others use it frequently. I would say FADCing is essential to using Ryu & Sagat. Others like Rufus and even Abel have nice FADC’s into Ultra 1. While just about every character has a use for FADCing, most are just for extra combo-damage, “get-out-of-jail-free-cards” if the move is blocked or to add pressure after a slow fireball. Many charge characters and grapplers don’t need to FADC too much.
Sagat’s lk. Kara into TU or TK is much easier than most kara’s. Ken’s toward+mk xx throw is an easy kara throw to tell if you’re doing it right. Ken moves forward a lot, so use the training room squares to test for yourself if you’re performing it right. Test a regular throw then a kara throw. It’s all about getting your fingers just the right distance apart so that when you press the buttons, the throw comes out slightly after the toward+mk. Or, you can just try to get used to the timing, but I found it much less reliable.
Kind of like kara throws. I try adjusting my fingers to where they hit the buttons at a frame or two apart. For practice, try these four p-links (p-links are in bold):
Sakura: cr. lk, cr. lp, cr. lp. + cr. mp xx special move —or— cr. lk, cr. lp, cr. lp. + cr. hp xx special move
Chun-Li: cr. lp x3, st. lp + st. hp
Akuma: (far) st. hk, cr. lk + cr. mk xx special move
Rufus: st. lk, st. lp + st. hp xx special move —or— st. lk, st. lp + st. mp xx special move
My Personal Take On The Topic:
I use a good chunk of the roster frequently, because it makes the game much more fun for me. I watch videos frequently and take good combos, strategies, resets, etc. people do to me in matches, and learn them in training mode. However, I’m currently scrub-like with about 90% of the cast when it comes to execution. What saves me is decent fundamentals and mind games (which only works consistently on intermediate and below players.)
I did learn some characters considerably more than others, just so I have a few that I can be somewhat competitive with. Unfortunately for me though, one of those (Sakura… who I’m probably best with as far as linking and execution goes) will always have trouble getting in on some characters. Those that she can get in on, she doesn’t want to be close to (Zangief.) So, I tried to learn characters that are somewhat the opposite of her, which lead me to Seth and Vega. Seth, like Sakura, is a stun machine but he also has good zoning tools and can hold his own up close. I play an altered hit-and-run Vega, but I throw in a lot of pokes, overheads, and throws with him. Matches I have trouble with when using Sakura are much easier for me with Vega (except blanka - he’s hard for both.)
There are many great articles on SRK, Eventhubs, Sonic Hurricane, etc. that can go more in depth about these topics. I’m not the best at linking, but for what it’s worth: My links suffer because I use most characters frequently. My timing gets thrown off because I can’t let my muscle memory get comfortable with one character. That alone might throw you off from wanting to use the whole cast.