Be aggressive. Be gamey. Exploit the AIs to the maximum.
For instance, if you are about to surprise attack someone and want 2000 or more gold quickly on one turn, offer the victim everything but your cities AND THEN declare war.
If you keep the tempo up, chances are the AIs will not only respect you, but they'll keep their distance away from you as possible. A good rule of thumb is to check the Demographics screen, and make sure you army is 1st or slightly 2nd place.
DO NOT, I repeat, DO NOT pause after early wave of conquests to settle down for long-term peace. There is none, and when you have a monster runaway like Wu Zetian who hates you since Antiquity for stealing the Porcelain Tower with a war dec, you will very very much want to have her defanged as thoroughly as possible before she reaches Industrial.
edit: Learn how to sell cities whenever your unhappiness goes past -11. If played right, you can sock the AI civs at each other instead of you for a long time.
edit2: Check out Tabarnak's Four Cities Sword Rush