What is the most effective way to have your defensive/offensive spells and effects in place for the start of a battle? I ask this because most enemies tend to already be buffed when battle starts. They have foreknowledge of our approach as our battles towards them tend to be loud, or we set off traps alerting them, of that one member of the party who wears full plate and no ranks in stealth (yes Im looking at you paladins and fighters). Whereas we generally dont know we are about to get into a fight until combat is upon us. Either we have entered into a new room or we are being ambushed.
When an effect is hours per level (or greater) like mage armor its much easier as 1-3 castings and your covered for the day. Its the ones that are 1 min per level or less that are the issue. Casting your buff/defensive spells in combat, while capable of turning the tide, are really expensive from an action economy view.
The metamagic feat quicken spell is one method but its very costly because it adds 4 levels to the spell but allows you to get it off as a swift action, which basically means you can get 2 spells out if your a high enough level.
The spell contingency is another expensive method but only allows a single spell to pop into effect at the start of a combat. It also depletes 2 spells to use.
As far as I know magic items suffer the same action limitations as it takes an action to drink a potion (and you cant have multiple potions mixed together for a single drink). Wands and scrolls generally only let a single spell get off. Yes there are feats and abilities which can allow you to get a second usage of these in.
So what can a party do to even out the starting action economy of a fight?