Self tanner can be a wonderful product, especially when you are trying to look slimmer. If you are going to be in a bikini, you'll look better if you are tan. A tan not only slims, but it accentuates the definition of muscle. The key of course, is getting it right so you don't streak or look orange.
The first thing you need to do is exfoliate. If you try to spray tanner on dead skin cells, it will just make it orange and uneven. While using a loofah in the shower is fine, the best way to exfoliate is with a scrub. Sugar scrubs are the best and will leave your skin soft and smooth. When you are exfoliating, pay special attention to areas like your elbows, knees, heels and any other area that is prone to getting dry, rough skin. Make sure to scrub your entire body using circular motions with your hands. When you get out of the shower, dry completely and do not put any lotion on your body.
Now you are ready to tan. Make sure you are completely dry or the tanner will streak. Two of the best "at home" tanning sprays are Neutrogena's sunless tanning micromist and L'oreal's Sublime Bronze spray. Begin spraying your legs in a circular motion, holding the bottle 4-6 inches away from your skin. Remember to always keep the bottle moving! Spraying too long in any area can result in an uneven tan. Be careful that you don't over spray on areas like your heels, hands, elbows and knees, as these areas then to soak up more color. The great thing about these products is you can spray upside down for hard to reach areas like your back without clogging the bottle. Make sure you've gotten every inch of your body, including your face (Neutrogena's tanner is oil-free).
The last step is to slim with contouring tricks. Many women tend to hold weight in their hips and thighs. Spray your outer hips and butt a few more times to make them darker, appearing slimmer. For the abdominals, spray vertical lines where the abdominals would naturally inward (on the outside of your belly button). You can also make a "six pack" where that would naturally occur. Be careful that you are contouring within reason (if you have a lot of weight to lose, you may just want to spray your hips and the sides of your stomach slightly darker so it seems realistic). Don't forget about the detail in areas like your arms where your triceps and shoulders would curve. If you need help and wonder what muscle detail is supposed to look like, use pictures of fitness models as a guide. Just because you aren't feeling as great as you should, doesn't mean you can't help the process along with a little illusion!