As for best combination...mobile artillery with tech support. Costs 800 and will do more damage for your dollar than just about anything else.

As ever, though, any of the tactics or combinations mentioned in the forums are neither perfect nor foolproof...a good player is adaptable and learns what is best to use in the current situation. The only way to get that experience is to get stuck in and have a go.

Try different units in different situations, even if at first they don't seem right. You'll end up learning what works and no longer be a n00b but, more importantly, you'll have a heap of fun playing.