You've heard them all before I'm sure but I find it helpful to be reminded of things I think I know.
PreSteinitz Chess was the battle of attackers if you were a better attacker you by all rights you should win.
Steinitz is considered to be the father of modern positional play.
He pointed out that
* Defense as well as Attack is important
* That there is a time when one should Attack and a times when one shouldn't.
* There are places on the board where one should Attack and places one shouldn't.
* It is one's Obligation to Attack when the time is right or else the advantage will slip away.
* Which ever part of the board the attacker has the advantage should be where he should attack.
* pawn weakness of the opponent, control of open lines and outpost squares are important
* the fight for positional advantage first not the kingside attack
*The Accumulation of Small Advantages is the basis for positional play.
Lasker promoted two big ideas based on Steinitz ideas.
1) The Principle of Economy - whoever is under attack must make concessions to defend himself but must make the smallest concession possible. Not an ounce more.
2) Strengthening the line of least resistance - the ideal situation is where all lines of resistance are equally strong with no weak link in the chain. Strengthen weak areas first. Be careful of Pawn Moves!