As for the really small pieces, I have trouble with them because I have difficulty holding them securely while taking flakes off. Bigger pieces, 1.5 inches and more are easier simply because I can hold them better.
As for technique, I think the technique for small pieces is the same as that for bigger ones, but scaled down to size. That last one would make a fine hunting point, and the Native Americans used a lot of points like that. If I were to trying to put a pretty pattern on it, I would use pressure flaking on a pad no more than 3/4 inch wide. You-tube has hundreds or thousands of videos on flint knapping covering every aspect and current method of knapping. Watch a lot of them. For those really small pieces I recommend pressure flaking. Search for pressure flaking on You-tube.
Platforms are the places you find or prepare so they are right for taking flakes off. They need to be located so the flake can follow a ridge and take the ridge off. The platform needs to be strong enough to take the flake you are intending to take.
Where are you located? Somebody on here may be close enough to meet you and give you a few pointers.
WA