My Tips for peaceful strategies (part 1):
1) Revenue from other CIVs can be
very profitable for you, whilst slowing them down at the same time

Here's how...
1.1) Early on in the game, explore and build cities close to as many luxury/strategic resources as you can

. They are a constant source of income for you throughout the entire game. If far away, don't forget to try and build it next to a costal square... You need the harbour to be able to trade it. If not, build a second city that IS on the coast, and connect them by road. You obviously need to build a harbour in this second city. This is a worthwhile endeavour for a constant income later.
1.2) Trades last 20 turns, but don't forget to review them at that time! If you become a more powerful CIV, the other CIVs will (usually) offer to pay MORE for that same luxury you traded 20 turns ago! of course, other CIVs with larger bank balances will pay more. :santa: I never used to do this in the beginning, but I found it a very porfitable endeavour.
1.3) When you have a high bank balance, other CIVs will review their trade with you after 20 turns, and expect you to be able to pay more for their luxuries/SRs. In my game, Fine German Dyes went up.. and up.. and UP!
1.4) If a CIV is annoying you by consistently attempting to move through your territory in order to get to other cities in their territory... Rather than constantly telling them to withdraw (and thus provoking a negative twist in attitude), offer a Rights of Passage agreement in return for GOLD-PER-TURN! It's unlikely they will ever drop this trade too.
(By the way, does anyone know how to stop them doing this? My stupid Indian friend is always every so polite, but I have to KEEP TELLING HIM to withdraw them. Then, the next turn, he just tries to move em all back again! Infuriating!!!)
Back with more tips later...
ApolloE