If you see that someone’s concerned almost entirely with your approach on the ground, a jump-in will probably be relatively safe (also depends on whether you’re safe jumping or whether they’ve got a fast reversal). For instance, if they like to stick something out every time you get into their max range, it’s a perfect opportunity for you to punish them for being predictable. They’ll be stuck in the recovery for the move while you land on them.
You have to spend more time looking for jump-in opportunities when playing footsies with characters that out-range/walk you by a lot like Claw (especially since his anti-air is relatively weak).
Always try to play a solid ground game first though. If they’re not afraid of your ground approach, then all they have to do is scout your jumps if they know you’re gonna keep relying on them, and jumps are mad easy to counter when you can see them coming.
You’ll find that some people with a seemingly good ground game are not leaving room for themselves to safely evade or punish jumps in the process. Against people who really understand how footsies work though, jump-ins are much harder to land safely.
It mostly has to do with reading your opponent, and it also depends what character you’re using. Someone like Cody or Blanka will have an easier time getting jump-ins than Cammy or Ryu.
Also keep in mind that wake-up games don’t have to mean attacking right when they get up.