The primary method for maximising the heat output from any stove, is of course a decent windshield. These can take many forms and usually prevent the wind taking the heat from the base of the pot. This keeps the base of the pot hot, however as heat rises it is generally being lost up the sides.
One excellent solution is the Caldera Cone, which performs an excellent job of containing the alcohol stove and trapping maximum heat up the rim of the pot.
This video shows you how to calculate and make a conical windshield which clips to your pot and which can be used over any heat source. Until the Caldera, it doesn’t rest on the ground and support the weight of the pot, so it can be made from lighter and more flexible material.