Mix about a gallon of quick-dry concrete according to its instructions.
Fill a coffee can with the wet concrete.
Set aside the coffee can until the concrete has dried. This may take one to two days.
Drop the concrete-filled coffee can repeatedly onto the area of earth you would like to compact. You should make sure to walk on the earth while you are doing this, since your added weight will contribute to the soil's compaction.
Continue to drop the coffee can and walk on the earth until it is sufficiently compacted. You will know that you have made progress when the earth appears flat and dense and is not easily disturbed.