Choose the network before anything else
This is worth more than every other item combined. The same swap can differ by two orders of magnitude in gas between Ethereum mainnet and a rollup or low-fee chain. No setting recovers that difference.
Check whether the pair you want has adequate depth on the cheaper network — if it does, there is nothing to think about.
Transact less often
Every transaction pays gas again. Four small buys cost four lots of gas and four lots of approval overhead; one larger buy pays once. If your plan is accumulation rather than timing, fewer and larger is simply cheaper.
The same applies to moving funds. Each hop between chains and wallets is a fee; plan the route once instead of discovering it one transaction at a time.
Stop paying for reverts
Reverted transactions cost full gas and achieve nothing. Diagnose the reason rather than retrying: a stale quote, a missing allowance, a tight tolerance on a volatile minute and a transfer-fee token are four different problems with four different fixes.
Keeping tolerance as tight as the pair allows also removes most of the sandwich exposure, which is a cost you were paying invisibly.
Housekeeping that pays for itself
Reuse an existing allowance rather than re-approving. Consolidate dust while gas is low rather than when you need it. Hold a small gas buffer on each network you use so you are never forced to bridge at a bad moment.
FBT Swap shows the route, the price impact and the 0.70% platform fee in the quote, so the comparison between networks takes seconds rather than guesswork.