to make it a far better game, turn off super weapons
if you're allies, brits are awesome because of the sniper, keep trying to trash his harvesters
the GI's that cost £300 (i think it's 300) the ones that fire rockets when you deploy them, are awesome, if you've got 10-15 of them, with around 3 snipers and 5 normal Gi's on the ore field, it'll take a lot to kill them
using your spy's is very important, and blocking his are more important, so buy a ton of dogs and set them to patrol your base (and keep watching the map). spy into his power plant = power down (and the heavy defences + radar) for 60 seconds, spy into his barracks & tank builder= all your new units will be promoted in training, and spy into his tech centre will give you a new unit (barracks)
having about 5 or 6 prism tanks in a line behind some deployed GI's will stop all light - medium attacks
best way to practise it keep playing an 8 player map against all brutal cpu teams, you'll soon learn how to defend!
-the games all work fine in xp and vista, although i don't have it installed as such, i just keep the RA2 folder on my external drive, and use a cracked exe for the game -the protection it uses really really doesn't like xp, so i was kinda forced to do that!