Questions to ask yourself
1. Does it take place before another event in the past?
Yes -> Past Perfect
No -> choose on the the Present tenses
2. Is it a one-time event or a situation that has been completed?
Yes -> Present Perfect
3. Is the situation still going on, has it been going on for a longer period of time?
Yes -> Present Perfect Continuous, UNLESS it is a state verb!
4. Is it a state verb?
Yes -> Present Perfect + 'for' or 'since'