Deck building conseil

I am trying to build a good deck on my copy of Yu-Gi-Oh! World Championship 2011 Over The Nexus and I need some tips.

I usually build like this:

20 Monsters
10 Spells
10 Traps

0-15 Fusion/Synchro

But I need a few tips on how to build a good Tuner deck.

How many of my 20 monsters should be Tuners? 5-10?

So please any tips toi have will be appreciated.