I have learned on this site that not all arrows/mounting will be perfect, so spinning you arrow with the broadhead is a good idea but I am not sure how to do it. What do i need to look for and how do i spin the arrow properly?

It' s a pretty simple process.........screw in a broadhead and on a smooth surface (like the back of a bow case etc.) stand the arrow up and spin it gently. if you see any wobble try the head in the rest of the arrows to see if you find one that it spins true on. If you can' t find one then you might have a problem with a bent ferrule on that head. Keep mixing and matching heads and arrows until you find as many as you can to spin true........the rest might be a matter of badly aligned inserts or like I said damaged or bent ferrules on a particular head, or in the case of aluminum arrows maybe a bent shaft.

And don' t go spinning the head like a madman or it might hop out of your hand and take somebody out!! []
You' ll know a good spin when you see it.......absolutely no wobble, just a pure even spin straight to the tip.

I agree pretty much with Matt, but I do recomend you either buy or make an arrow spinner. They are fairly cheap at 25 bucks or so and well worth the cost when it comes to putting together the best possible hunting arrows.

I built a spin tester.
My neighbour gave me some stuff he had laying around so the total cost to me was 5 minutes of my time

I use a spin tester....Its shocking to see how much some factory arrows are out of alignment