We cannot stress enough how important it is to prep your skin before self-tanning. Applying self-tan over skin that hasn't been exfoliated will mean that the tan will fade as the cells will shed. By exfoliating beforehand, you will notice a difference in the strength in the tan.
After scrubbing leave the skin clear of oil and moisturizer, this is what causes streaks and blotches. Clear, clean skin is all you need. (Only apply moisturizer to drier parts of the body, i.e. elbows, knees, wrists, knuckles.
Using a tanning mitt will ensure a streak-free finish. Sweeping motions are better than circular motions as they distribute the product more evenly, ensuring you have a flawless result.
One of the most problematic areas when self-tanning are dry areas, like hands and feet. Using a kabuki brush, pick up a tiny amount of self-tan (or the residue product left on the tanning mitt), your hands and feet should be the last part that you tan; just brush the kabuki brush or tanning mitt over them lightly.
Leave tan on for 4-6 hours before showering off, moisturize if needed, the tan should last up to 1 week.