Just bought new radio an speakers for my boat. My questions is whats the best way to wire up the speakers to my amp, in series or parallel I have 6 speakers total.

It comes down to the resistance of the speakers, and the output capability of your radio. If you are going to run the speakers directly off the amplifier in the head unit with no external amplifier, the head unit's amp is usually 4ohm or greater required resistance.

Wiring speakers in series increases the resistance, wiring in parallel decreases the resistance. See this page for a good explanation: http://www.termpro.com/articles/spkrz.html

We need more info.. What radio amp and speakers.. Are they all 6 inch full range or are 2 of them subs.. What ohm are the speakers?