Creosote consists of flammable compounds escape your stove without being fully burned, and then cool and condense in your stovepipe. Ensure that you are burning your fuel as completely as possible to minimize the amount of flammable compounds that end up in your chimney.
Avoid smoldering or “choking” your fire by keeping the air controls relatively open, and making gradual changes as you adjust your burn rate. Whenever possible, reduce the stove’s primary air (bottom of the firebox) first, and feed your fire primarily with secondary air (top of the firebox). The secondary air mixes extra oxygen with any unburned flue gases while they’re still in the firebox, which can allow the gases to burn more completely before exiting the stove.