Fly tying is all about controlling your thread and keeping adequate tension. Buy several different thread materials...some stretch, some dont.
If I were to start all over again, I'd of tied smaller baitfish patterns to begin with. It is easier to tie moderate sized "flies" than say a BWO in my opinion.
Youtube is your friend, Some great channels to check out are Flyfishfood, Gunnar Brammer, or Fly fishing the ozarks.
Some marabou, Chenille, and schlappen can make just about every baitfish or crawdad pattern. Youll want thicker thread with these. Add some dumbbell eyes and some zap a gap glue and you are golden.
Learn the whip finish without the tool.
Ive also never had the gamakatsu b10s hooks ever fail me.
Size #1 to #4.
Check out hobby stores for material when you get down the basics...you will save money on certain items.