What's your average daily intake at the moment? Also is your diet running a surplus, deficit or balanced daily calorie input to activity?
One approach is to use compounds like press ups to surface the weak link in the chain - then do 'accessory' work to build strength in this area and then go back to your compound and you should be able to do more reps/ load. So for triceps something like lying tricep extensions, French press etc'.
I would normally persist and persevere with a compound due to its overall mass building for strength and size. However if you hit a genuine plateau - ie no more reps or weight for 3 consecutive workouts, then the accessory work would be where I would go next.
If you don't buy it then you can't eat it. Sort yourself out!
Depends what your goal is. If you're still looking to do 30 straight press ups in one set then I would stick at 3x10 and rather than adding reps or sets, I would gradually reduce the rest between sets slowly.
Its a flawed response that most lifters fall into, that when they plateau that they try to volume their way out. There's usually two reasons -
1. Something wrong with diet, sleep, form, recovery etc, or the intensity is too low
2. They've reached the natural end of that cycle of improvement and they need to lay off and let their CNS recover