Once a component location’s armour is stripped off, every hit thereafter has a chance of hitting a critical location of a piece of equipment mounted inside that location. That means that some weapons that cause multiple hits have a greater chance of causing critical damage – we call these crit seeking weapons.
The ultimate crit seeker is the humble machine gun. It has no range, but each “shot” is actually five hits, each of which could cause critical damage. If you have a melee build ‘Mech with machine guns as your supporting weapons, then you can open up the armour with a punch, and then crit seek with the machine guns with great potential effect.
LRMs and SRMs are also crit-seeking to some extent. In general, if a target has multiple breached armour locations, then hitting them with missiles is a good way to cause them additional inconvenience. It would also suggest using missiles and crit seekers after your big hole-punching weapons.