Which readings would you use to pronounce people's names?

I'm confused whether it is normally appropriate to use On-readings or Kun-readings when dealing with people's names; I'm fine when its just two character names; I just make a logical deduction in my head to how to say their name; but when I try to pronounce names with 3 kanji together, I'm completely lost.

I'll bring in examples at a later time, this computer can't easily type kanji.

Answer

I don't think there is a "normally" appropriate way. My personal philosophy is never assume you can read someone's name.

I suppose last names are easier to make a correct (educated) guess. It seems like they more often use kun-yomi. But they could be on-yomi, or other, lesser-used kun-yomi. I have two friends whose last names are the kanji 金城. However, one of them is かねしろ and the other is きんじょう. 吉田? Seen it as both よしだ and きちだ.

First names are a whole other story. From what I've heard and researched, it seems that Japanese people are allowed to basically associate any kanji they want with any reading they want. Kind of like how it's trendy these days to make up your own spellings for English names ('Lynzee', 'Linzy', Davyd', 'Markis', etc.) So your friend 良 could be the よし or りょう, but he could be something completely off-the-wall like ちから or あきら. Or 真 could be ま, まこと, しん, のぶ, or some other, random reading.

Never assume you can read someone's name. That is why when you fill out paperwork (application forms, official documents, etc.), they make you fill out the furigana for your kanji.