4.Tactical Plan. One should try to mentally formulate at least a simple plan, then also try to follow it. The plan should give a general idea of where the pieces are going to develop and what pawn moves are intended. Move order is also important and should be examined as well.
Generally speaking, pawn moves are made first (to gain control of the centre), knight moves come next (because they have few possible squares to develop) and then bishop moves (because bishops can be developed on several possible squares one may be uncertain which one is best). Castling should be done early, if possible, and finally development of the heavy pieces can also be done. Early queen moves are not recommended, for the opponent may take advantage by threatening the queen whilst developing his own pieces.
Next comes an example of how one should think when playing the opening.
Suppose WHITE is preparing his first move. There are eight pawns, each of which may advance one or two squares. The other pieces are currently immobilized, except for the two knights, which can move to two possible squares each. WHITE should recall the basic guidelines : development, control of the center, king safety, a tactical lan. He may well move a knight to start the development. The moves 1.Nf3 and 1.Nc3 are equally good, however, a knight on a3 or h3 is badly placed, for it is away from the center. Usually pawn moves are made first, so 1.e4, controlling d5 and f5 is a very good choice. Equally good is 1.d4 and 1.c4. The move 1.f4 is acceptable, but it weakens the king somewhat. Moving the a, b, g or h pawns is not suggested, since they do not fight for the centre. Similarly, 1.e3 and 1.d3 are acceptable moves, but they are considered inferior for the same reason.
Suppose WHITE eventually decides to play 1.e4 and now BLACK replies with 1…e5, also fighting for the center. Now WHITE has more choices, since his queen and his bishop at f1 can also move. WHITE should avoid playing the queen too early, as mentioned. He should rather try to develop his lightweight pieces. His selection list should now include at least the following moves, which are consistent to the basic principles : 2.d4, 2.Nf3, 2.Nc3, 2.Bc4. There are good moves too, but these are probably the best. WHITE should dislike for example 2.Bd3, because this move, though actually developing a piece, has two drawbacks : it does not increase the bishop's mobility and it prevents the d pawn from advancing. The d pawn will need to advance sooner or later, or WHITE will have little freedom in his moves; so the move 2.Bd3 may be a lost tempo, if WHITE later needs to move the bishop again. This mini example demonstrates how one should use his own judgment along with the general opening principles. Note that the general principles by no means are of universal validity.
