We have studied and developed many techniques and have to rewrite the SMW tricks page, but most of them are hard to explain even in Japanese. Anyway, I try my best.
Suppose that mario's x position is 0 when he is touching the left side of a block one wants to pass through and that his y position is 0 when landing on the block. Assume that he is going to the right. One can pass through the block if mario is going into the blue zone and if he is not going into the red zone. So in a usual case, x speed needs to be 49 or more and y speed 33 or more. For example, one gets through the corner when mario is flying to the left (in x speed 51) as (-4,1)→(-1,-2)→(2,-5)→(6,-8), and so on. It is easy to reread these conditions when mario is moving to the left. Please care that one cannot get it when mario is moving to the right and when mario is small or ducking. When with yoshi, we are less aware of the condition; ISM got it with y speed 16.
Next let me try to explain how to get going up higher when catching air. For this one should know how to cancel a higher air-catch, which is explained in
my movie's topic. Now assume that mario is flying to the right. After putting mario into the diving animation, press X (or Y) to cape-spin in such a way that mario ends up facing left after a cape-spin stops, and catch air just before a cape-spin stops. Then mario gets going up a little, but since a higher air-catch is cancelled he is still able to get a higher air-catch without getting the diving animation again. So pressing X before mario starts falling makes him face right and get a higher air-catch again.
For flight tricks, the following addresses are useful:
7E0076: the direction mario faces;
7E1407: mario's flight animation.
I hope these help you :)