If you arent that far behind in life, laser, fly, unfly, laser is pritty safe and forces them to go on the offensive, making them prone to pans or unblockables.
When against storm, she will most likely take to the skys and run, so sj. before her and catch her with a pan to the face and stomp on her until she gets out of it. When she does, dont bother chasing after her once she is above you cuz her hp will beat you out. fly to a point where she wont hit you on the way down and unblockable/stomp.
Against mags, Laser and low flying HPs work wonders. dont stomp on him since if you have a hole it leads to an infinate. Also if you are stomping you are closing the gap between he and you and thats not good. Also what is really underrated is his standing laser against magneto, throw this out once in a while since it will often hit magneto where mags would jump over his crouching laser. actually standing lasers work well against storms too.
Against another sentinal it is a battle for the skys. If you are on top of them stomp away. If you are below, pushblock and superjump pan. nothing fancy here. Whoever uses their pushblocks and unflys the pest will win.
If you are really far behind and they have an anti air, what i would do would be to zone them to the corner (either by lasers and flying back and letting them chase me, or by simply jumping forward with few attacks so i wont get hit by anti airs) once there, you can go for cross ups like c. lk mp xx fly f.lk f.hk rp or whatever, but ideally you would catch them with a ground rp into HSF. If they arent going for your cross ups, try to throw them in the corner which is just as good. Guard break the next two people and thats game.
Its already been said but dont use specials unless you have full bars, you need it to cover a missed laser or if it will kill the char. To comeback you absolutly need those specials to do real damage.
Damn i need to study.