The trick is to be organised. An ideal "kit" comprises of - shower, body brush/scrub to exfoliate the skin, hand basin complete with soap and nailbrush, skin lotion, sponge, a clock and of course the chosen product! Most people use the bathroom - so remove all the towels. Often we get the temptation just to use them for a quick wipe.
Next thing to do when applying self tan is to exfoliate the skin. By exfoliating the skin we remove the dead skin cells as well as any excess body oils that could inhibit the absorption of the applied solution. Concentrate on your knees, ankles, feet and elbows. Most of us will do this when we shower or bath - try and use only a mild soap as this can affect the pH of our skin and the active ingredient (DHA) in most solutions is sensitive to pH changes.
As most of us will insist on doing all this in the bathroom - give the bathroom a chance to dry after your shower and let any condensation evaporate. Being in a hot stuffy bathroom will cause the skin to perspire which is perfect if you want to develop a streaky effect.
Exfoliation is always followed by moisturising. Except that by applying a moisturiser we can risk blocking up our pores thus minimising the absorption of the tanning solution. The exception does apply to feet, elbows, hands and feet which tend to allow more solution to be absorbed.
Remember that what ever you are wearing will decide where any tan lines will end up. Tight fitting dark clothes are the answer - dark so they don't stain and tight so the solution doesn't seep under. Any clothes put on afterwards should also be dark cotton and loosely fitted so they do not erode at your new bronze look. Any colour that rubs off can usually be washed out during a normal wash cycle.
Shake the bottle and mix it up well - the product has been sitting undisturbed on the shelf so obviously it has separated to some degree and using it in this state is going to lead to streaking.
Whether applying a gel, spray or lotion the best technique for ensuring the most even application is to use a circular motion when you are massaging the product in - not an up and down motion!
When you start take a look at the clock - wash your hands every 5 minutes to avoid staining. Use the nailbrush on your nails; wash your palms, between your fingers, your knuckles, and the sides of your hands.
Never apply the self tan product directly to your hands, feet, knees, and elbows! Instead spread the self tanner on from nearby areas. Once you have done this moisten a tissue and LIGHTLY pass it over. It is the area just below the knee and the part of the elbow that bunches up when your arm is out straight, which tend to over darken the most.
For hands and feet (especially around the fingers and toes) is to place a small amount of product into a saucer and then with an "eye shadow brush" paint your tan on.
When confronted with your face and neck, remember these areas absorb colour quite well so use the product sparingly. A key area where less is definitely more is the forehead hairline area.
Once you are covered from head to toe, try and stay away from everything for at least 15 minutes (including clothes.) Give yourself lots of "naked time!" Products work best when given plenty of uninterrupted drying time.
Now that I have it how do I make it last? To stay looking brown avoid water and all its many forms for the first three hours (this includes sweating) and only have a bath/shower once 8 hours have passed. Moisturising regularly will extend the product's life.