Easy techniques to study if clause

If the given sentence is in past perfect (had  v3 form of the verb)

The main clause should be would/could/should/might/  have plus v3 form)

If the given sentence is in simple past (did  verb)

main clause should be would/should/put/might

If the given sentence is in simple present(do/does  verb)

main clause should be simple future (will/shall/can/may)