Defensive Tactics

Use blocks to inflict pain.

Use parries to unbalance opponent.

Use body movement to avoid attack.

Beat opponent to punch.

Block hard to break opponents balance

Parry (deflect) attacks when possible rather than blocking. It is quicker and permits quicker counterattacks

Keep guard up, hands high, elbows tucked in.

Jam a kick as it is cocked to prevent the kick from firing.

Use a beat for a counterattack. It is quicker and more difficult for the opponent to block (Beating is bouncing a block off the opponent's attack into an immediate counterattack)

Your defense has to facilitate your offense. Everything "defensive" is really a matter of doing AS LITTLE AS POSSIBLE to make opponent miss, while not messing up your alignment to hit back. There is no need for multi-step blocking or highly eccentric movements

As Musashi says, "Do nothing that is without a reason." Beware of gratuitous and wasteful motions that do not serve any purpose. For example, jab when you slip a jab. Cross when you slip a cross. Etc. The thing that weakens an opponent's offense is your own offense. Everything else (e.g. slipping without countering, blocking as an isolated movement) is just prolonging the inevitable.