Ashi-Barai key points
a) De-Ashi-Barai is done with a sweep to uke's ankle
b) Ideally done on the move
c) Tsubame-Gaeshi is a counter to De-Ashi-Barai. When uke sweeps, tori gets out of the way and launches his own footsweep on uke. This is Tsubame-Gaeshi.
d) Okuri-Ashi-Barai is similar to De-Ashi-Barai except both feet are swept.

Sasae-Tsurikomi-Ashi & Hiza-Guruma's key points
a) Sasae is a block with the sole of tori's foot.
b) Tori makes a little run to the side and forces uke to take a step forward
c) Keep the blockin leg straight.
d) Hands will lift and pull
e) Hiza-Guruma is similar to Sasae except the leg blocks the knee rather than the shin
f) Tori can use his calf instead of his sole to block uke's knee
g) The hands do a steering/wheeling action rather than a lifting/pulling action.