Easy. For each wire, determine if it's 10 AWG, 12 AWG, or 14 AWG wire. Then consider the following table:
- 14 AWG, 15 amp breaker
- 12 AWG, 20A breaker
- 10 AWG, 30A breaker
Don't upsize any breakers. But if the breaker is bigger (in amps) than the wire in the above table, downsize the breaker. BR breakers cost $5 for a single and $10 for a double.
Any wrong-type breakers (looking at you Square D), replace them.
If any cables have 2 hots (e.g. red-black-white Romex) get a 2-pole breaker of appropriate amperage and land both hots on the 2-pole. Note a 2-pole is not a duplex. A 2-pole is twice the size of a normal breaker.
That's it. You're done.
After this, some loads may trip the breaker. If that's the case you'll have to follow the usual troubleshooting - too many loads on one circuit, too small cable needed, etc.
If a breaker serves only one motor load, ask a new question with the motor specs and ask whether you can use (size of wire you have) with (size of breaker you used to have).