In modern warfare 3, or in any first person shooter for that matter, mobility is something that is underused and under appreciated. Now Halo jumping around every corner isn’t going to do you much good, but tactically moving the map and using the mini map to it’s fullest potential can often give you great insight into were the enemies are likely to be hiding and thus will let you know when you should get ready to use all the mobility at your disposal to out maneuver your opponent.
Using every mobility option includes, but isn’t limited to, jumping, proning and strafing. Simply crouching can often times avoid a death because recoil is upward and you lower your profile considerably by crouching which means that often times your opponent will loose you in their sights.
The mini map can be used in many different ways. The primary is that you locate enemies. In fact that is all I look at when I know that there are no enemies around me. By analyzing it over and over and thinking about were the enemies are probably at you can often work out the best routes to move and thus know when you have to employ your maneuvering tactics. You should always also remember common campspots and traffic patterns.