> does parity matter ?
Using parity SIMMs on no-parity systems is usually no problem (for 30-pin and PS/2 SIMMs, different story for DIMMs).
> edo or fpm does it matter?
EDO can work faster if the RAM controller is designed to make use of this feature (don't think any Amiga hardware is). Some non-EDO RAM controllers don't like EDO, so you'd need FPM.
> are tin conectors ok?
The contact material (gold vs tin) of the SIMMs should match that of the sockets. Otherwise a gradual chemical reaction will degrade the contact quality over the course of months/years and require you to 'vigorously reseat' the SIMMs every once in a while. Mismatching contacts is a no-no in systems you heavily rely on (servers and such).
> what to avoid?
- before handling RAM (or other chips) make sure you've grounded yourself and the system you're working on to have all static electricity discharged
- discharging through chips kills them instantly or severly shortens life
- move as little as possible to avoid getting statically charged again
- avoid touching conducting areas, handle at edges only