Set up your mics as you normally would to play or record. Each mic attached to a specific piece of your kit should be as close to that drum as possible and pointed downward. Drum condenser mics have a very narrow range of area they pick out sounds from, so they must be pointed directly at the sound sources to get a high volume of input.
Run your drum mics through an audio gate if you are playing in a live performance. Gates set minimum levels of decibels that must be produced by the sound to allow the signal through. For example, if you plan on playing your snare loudly and consistently during the performance, you need to set the threshold of the gate rather high. Any hits that are softer will not open the gate for a signal to come through. Thus, all sounds bleeding into the mic while the snare is not played will not be loud enough to get through the gate.
Connect your drums to your mixer or interface if you are recording drum tracks. Don't use a physical, or hardware gate to record because anything that is accidentally played too lightly will be cut out from the recording. There is no way to recover this audio if it is cut out before it is written to the system.
Load your editing software and create a different track for each drum mic. Have the drummer play to test these tracks while you set levels to be as loud as possible without clipping, or passing 0 db.
Record the drum track as many times as it takes to get two solid performances.
Load a software gate plug-in -- a computerized version of a real gate -- to the program. You can put a different gate on each track to set and change thresholds along with the dynamics of a song. Or, you can put a single gate on an auxiliary track, which is less effective but saves on processing power. Gates should be used after recording so you can adjust them freely to keep from losing important hits.
Play and edit each individual track, making sure to get the maximum usage out of your gates through level automations. If you have low-quality mics or gate plug-ins, you will be able to hear a higher degree of noise bleeding through. It will only be audible, however, when your instrument set to each mic passes the gate's threshold. Thus, until you hit a tom, nothing will be audible through that tom's mic. But when you hit it, it may let in other sounds. For this reason, you want the tom to be as loud as possible while recording. You can always reduce its level afterward and cause the bleeding noise to disappear or become so faint that it is unnoticeable when all tracks are played at once.