What is the most effective way to cluster MySQL for my requirements?
It depends on how you use your database. If it is read-heavy but with few writes (like a blog or a news paper) you could have one mysql for writes and two for reads. You would set up so the write server is a replication master and the two for reads are slaves.

All application servers needs to know about both the write server and one of the read servers, that way when you balance the loads to application servers you automatically balance the reads between the mysql servers. It's also easy to add another mysql+application server once the need is bigger.

If you on the other hand have a write heavy site (I can't even find an example) you need to do some research on sharding. It's normally not recommended unless you really need it.