Crouch teching is neat in one particular game, but…it probably shouldn’t be the first thing you learn about throw teching. The most important thing is to try to predict when people are likely to throw you, because while SFIV throws are relatively slow they’re not something you can break on 100% reaction to the actual animation unless you have absolutely god like reflexes offline.
One of the typical cues in lower level play (this can get you blown the fuck up at some point when people start baiting with it but it’s something you just sort of have to deal with) is when people stand up from their block string, which gives you a couple extra frames at worst, and hopefully they’ll have to walk a little ways but that’s not always the case. Another time you can often read a throw (this can also get you blown the fuck up for the same reason) is if they do a heavy jump in attack but don’t immediately press another normal or start blocking, in which case they may be waiting for blockstun to end so they can throw. Similarly if they jump and don’t press a button they may be trying to avoid putting you in blockstun entirely, although there’s also an empty jump into low mixup that’s not as strong in this game as some others and if they do empty jump uppercut (this is a shenanigan you’ll mostly only see against people who are either straight up bad or just desperate until you start seeing option selects, which in the latter case is somewhat easier to read, but it’s especially worth watching for if they can FADC) that’s going to look bad, although the answer to that situation was mentioned above.
If you’re playing most players without really unpredictable offense you should be able to get some sort of feel as to when they’re likely to throw eventually which will help you across other similar games. I mean, there are some random fools that will take a little longer to figure out and they will annoy the hell out of you in ranked matches but that’s life. Crouch tech is more an intermediate thing for when people get really dangerous with their throw mixups and taking a throw can cost you half your life from the ensuing safe jump, but it’s in your best interest to understand throw setups regardless because you’re going to have to deal with command throws and traps that ensue from them.