tune how? adjust gain? adjust crossovers?
this question is too general.
without proper tools, you can only make subjective changes by using your ear with proper test CD's. if your ear is untrained or you don't have test CD's, then tuning by ear is less effective.
best way to tune an amp is to pay a professional to do it and teach you.
i used Test CD's, a DMM, and an oscilloscope.
if someone don't own or know how to use a DMM, i don't think they should be installing amplifiers. proper installation requires a minimum amount of knowledge to be safe about it.