Nail polish will last longer and perform better when stored upright, in a cool, dark place. Always keep nail polish out of direct sunlight. Direct sunlight can bleach the pigments in nail polish and permanently change the color.
Be sure to keep the threads of the bottle clean and free of any dried polish. Wipe them regularly with a cotton ball soaked in nail polish remover. Failure to keep the threads clean will allow air into the bottle and thicken the polish. Nail polish thinner (NEVER nail polish remover) can be added in small amounts at a time to restore thickened nail polish to its original consistency.
Most nail polishes require at least two coats to cover the nail completely. Coats should be applied thinly and evenly with adequate drying time between coats to avoid air bubbles and tacky polish. Always wait until your first coat is dry to the touch (this can be anywhere between 5 and 10 minutes, depending on the polish) before adding a second coat.
Glitter polish can be tricky to work with. Large, heavy glitters can sink to the bottom of a polish over time due to their weight. If you're having trouble getting large glitters out of a polish, sit the bottle upside-down for a few minutes to move those glitters to the top of the bottle.
Dense glitters will need to be applied using the "dabbing" method, rather than with a regular stroke. Get glitter on the nail polish brush and press the brush into the nail, using the brush to move and manipulate the glitter on the nail until you've achieved the desired look.
Glitter can also be applied with a toothpick using the "glitter placement" method. This is done by pulling the glitter out of the bottle (or from a glob of polish on a piece of paper) and deliberately placing the glitters where you want them on the nail, one at a time. This can be time consuming, but the results are amazing.
Glitter polishes can also be thicker than others. Full coverage can easily be achieved with glitter polishes by applying the polish to a makeup sponge and sponging the glitter onto the nail.
Removing glitter polish is difficult. The easiest ways to do it are to use a peel-off basecoat (this will shorten the life of the manicure, however) or to soak pieces of cotton ball in acetone and place them on the nail, wrapping them in foil to maintain contact with the nail. Sit like this for 5-10 minutes and then slowly remove the foil, pulling the cotton ball across your nail as you remove it.
Topcoat is crucial to a manicure for many reasons. It will protect the polish from chipping, add shine, and thicken the overall manicure, protecting weak nails from breaks.
A lot of indie polishes tend to dry dull due to the ingredients available to indie makers. Topcoat will bring those polishes to life and make any shimmers and microglitters stand out.
Micro and chunky glitters can dry very gritty or lumpy. A good thick topcoat (sometimes two coats of it) will be needed to smooth out those polishes and make them look glassy.
Some holographic polishes and be dulled by topcoat. Always test topcoats out with holos by applying them and letting them completely dry before decideding if the holographic effect has been dulled.
Fast drying topcoats should always be applied over wet polish to avoid shrinkage and peeling.