As White, I like to open up lines of attack.
I like to combine the ideas of Protected Advance, not making my pieces targets if possible (think mobility/flexibility), taking away squares from pieces with pawns, the concept of the Outpost, and making threatening moves.

That said, I like the Vienna Gambit.

In General, open up one path each per bishop (there are exceptions, there always are....)
In General, I think the most Natural squares for the white knights are on c3 and f3 because they are protected by pawns (an outpost) and are aimed towards the center, which from there, they have the most avenues of attack. Less common are h3 and a3 because on those squares they are natural targets by the bishops when a centeral pawn is pushed! However, if the b or g pawn isnt pushed, that would make it (protected)..... d2 and e2 are possible too, but, isnt as natural as the other moves mentioned because it isnt protected by a pawn (but if its not a target in the first place, why worry, right?!) Later, the placement of knights will determine basic tactics in the middle-game, so it all depends and usually, besides the pawn, the knight is the first piece to be developed, which can make it be a tough decision. Now c3, I believe is more natural than f3 because it doesnt block the queen from moving out after the efficient e4 is played. (efficient because it opens up 2 diagonal moving pieces in 1 move)
In General, the rook goes to either the open or half open file as soon as one of the pawns are traded. If e or f pawn is traded for example, casteling king side may be the way to go. If the c pawn is traded, after the queen's knight and queen's bishop move, Rc1 is usually good. Sometimes, if the d-pawn is traded, casteling queen-side is considered.
If my opponent has fienchettoed the king's bishop then Bc4 (attacking the base of the pawn chain is recommended)
If my opponent has played e6 and developed the bishop the other way then Bd3 attacking the h pawn (tactics usually present themselves after casteled), but your e pawn must be traded, pushed beyond e4, or just out of the way for the king-side target. (like against the French)
The Queen has the most functionality (generally) and therefore must be valued more highly. Dont make that piece an easy target (generally)

This is my general opening development scheme. Please add to it or critisize. Thanks.

It is difficult to criticise it as it is the standard opening scheme that most of us probably use.

Crash

Thanks, I found that helpful. I like aggressive openings myself (probably because I'm not good enough to know better). KPG for White, Petrov, Alekhine for Black. That's why your post is helpful, looks like a more reasonable development scheme ...