Psssst, if an opponent can do ANYTHING out of your combination of grabs... IT IS NOT A CHAIN GRAB even if they have lvl 9 predictable DI (Directional Influence)
I used to practice basic up throw combos on Fox and Falco to understand the timing of the up throw and forward airs for each character, and then set them to evade to practice for basic DIing away combos. Then you just practice doing things out of DJCs or tilts, and practice basic tech skills like Wavedashing, DJCs, L-cancels, and I practice teleporting to the ledge from various directions as well as infinite stalls. If your tech skill is razor sharp, you don't have to practice it as much and then you can spend less time on it and more time just playing people to find things you can do to the average person and the advanced person or both.