1. Material relationship between the forces.
2. Presence of direct threats.
3. Position of the kings, their safety.
4. Possession of open lines.
5. Pawn structures, weak and strong squares.
6. The centre and space.
7. Development and the position of pieces.
As a result of comparing these elements the chess player makes a statistical evaluation of the position, selects a plan of action and begins searching for specific moves and calculating variations.http://www.chessvibes.com/reviews/review-find-the-right-plan-with-anatoly-karpov/