Just finished Marketing Warfare by Al Ries and Jack Trout. GREAT book. Here are the relevant ideas. Most of them are quotes from Karl von Clausewitz's
'On War' on which the marketing book is based. Great parallels and ideas.

The principle of force: "the greatest possible number of troops whould be brought into action at the decisive point"

The superiority of the defense: " the defensive form of war is in itself stronger than then offense"

The strategic square. Four types of warfare (with their principles)
1.defensive
a.only the market leader should consider playing defense
b. the best defensive strategy is the courage to attack yourself
c. strong competitive moves should always be blocked

2. attacking
a.the main consideration is the strength of the leader's position
b. find a weakness in the leader's strength and attack at that point
c. launch the attack on as narrow a front as possible

3 flanking
a. a good flanking move must be made into an uncontested area
b. tactical surprise out to be an important element of the plan
c. the pursuit is just as critical as the attack itself

4. guerilla
a. find a segment of the market small enough to defend
b.no matter how successfuly you become, never act like the leader
c. be prepared to bug out at a moment's notice