One of the basic tricks, is to cut down the number
of good Stats a PC needs. Most of the top Casters
can be narrowed to their casting Stat, but with a
little Con early on for survival.
So say you have a Cleric and you snag a 1 or 2
level dip into a non-core class or PrC that has
+Wisdom to attack or damage or both. Bonus!
Say you want a Monk and instead go Monk 1 or 2
and Druid 18+ ... you are quite the Monk then.
Non-casters have an odd quirk in multiclassing
where a small pile of classes are taken for just
2 levels each. It looks funny on paper, but it works.