Also what are good national ideas? I got the one that reduces inflation, quest and one that increases colonists.
WARNING: Longish post on how I pick ideas to follow. There are plenty of decent ideas to pick from based on what you want to do. The lower ones, like Scientific Revolution, Regimental System, Espirit d'Corps (those are just ones I remember off the top of my head) are generally awesome, but they aren't available until much later on.
I find Battlefield Commissions is very useful throughout the game--it makes your generals better, and you sometimes get free generals via events. Military Drill is also very useful early on, because your starting morale is usually around 2 and a +1 bonus is essentially a 50% improvement. You will basically win any battle you commit your troops to, because the enemy will flee before your troops break. However, it loses power as time goes on.
If you are into the trading game, I suggest Shrewd Commercial Practices and National Trade Policy, which both beef up your compete chance and your trade efficiency, which pumps up your income from centers of trade. They are pretty solid.
Some ideas are useful no matter what, like National Bank. It gives you more freedom to mint, keeps inflation low, and lets you amass cash for upgrading provinces (which is why I love it). Patron of the Arts is another one that's really useful, but not at first glance--all that cultural tradition gives you great advisors, usually 5s and 6s, and it enables some awesome events that give you great slider moves.
The #1 naval idea in my eyes is Press Gangs (I think that's what its called). It cuts all ship costs by 50%. That's both construction and maintenance costs. Given that big ships usually cost you around 50 ducats, cutting that down lets you build a decent fleet for cheap.
If you are down for colonizing, then the colonizing ideas (Quest for the New World, Land of Opportunity, the one that gives extra colonists) are good picks.