[TerranC]

Although this question has been answered many, many times, I thought I'd put in a little comment:

In my usual AI games, I always research beams first and missles later... But thats not the point.

The Point is:

After I get the Maximum level of Engine destroying missles and Capital Missles, I get a Light Cruiser, Load it up with the basics, Quantum Reactor, One Mulitplex tracking and many missles I can fit in with a ratio of 2 EDM for 1 CSM.

After that, Although I only use this ship for One on One or Capturing Ships and killing the escorts, I fire the Engine Destroying Missles (sorry, I forget the name) first, then the CSMs later.

Also, I make sure that the ships have equal leverage against the opponents:

Escorts-Light Cruisers - One ship.
Cruiser/Battle Cruiser - Two Ship. (Preferred Three ships as with two, you will probably lose one to the battle cruiser.)
Anything Up - 4-6 Ships.

Large Fleet - 10 Ships.

This worked for me, I really don't know if it will work against human players.