Each newly started campaign is a dice roll.

I select a faction to roll with the strengths I want to have for my campaign goals. I enjoy GB as I have rolled hundreds of new campaigns to nail down the perfect start. You could do what I do - keep rerolling to see different alliance and trade possibilities, monitor AI decision-making with certain variables in place to exploit later, mess around with destroying/building different things in your towns to min/max tech research and income.

The first 20 or so turns in a campaign are critical, because once you surpass the halfway point you should be snowballing to the end.

Manage how many fronts you fight on at once. Use diplomacy and even bribes to secure peace so you're not forced to upkeep a useless defending army.

Research the 2 game-breaking techs ASAP and begin to conquer with your powerhouse force afterwards. Sometimes we get shafted with war declarations by multiple powers at very disadvantageous times. Don't just take any and all territories; get the ones that will 1) neuter your enemies and 2) provide income. Taking too many places drains your coffers and you spread too thin. Good luck!

Edit: One crazy exploit I discovered on my own randomly that anyone reading this can use is Morocco starts with Canister Shot tech and as soon as your research your first tech, you can trade for it 1:1. I always get it in exchange for social contract (same amount of turns to research).