Roughen up the tops of your nails with the finer side of an emery board: It's the beige side, not the orange side. A few strokes across the tops of your nails will do it. You're not trying to thin your nail down; you only want to roughen it a bit so the acrylic adheres more readily.
Place a small dot of bonding agent in the middle of each nail. The agent will quickly be absorbed throughout all of your nail. If you use too much, it might make your nail bed feel like it's burning or stinging, so apply only the dot.
Open the powder and monomer and place them side by side within reach. Dip the tip of your nailbrush into the monomer, allowing the brush to soak up the liquid. Lightly nose the tip of the brush into the powder just enough to pick up a small ball of acrylic. Do not stick the brush down into the powder; doing so will cause hard lumps of acrylic to form within the brush, making smooth application difficult.
Place the ball of acrylic onto the center of one nail, back toward the cuticle. Flatten the ball with the bristles of the brush and pull the brush down toward the end of your nail slowly. Stroke the brush along each side of the nail to distribute the acrylic over the entire nail. Do not get this finishing substance on your skin. If you do, scrape it off before it has a chance to harden.
Remove excess acrylic from the brush by rubbing it on a paper towel. Repeat the process for your other nails. Allow 10 minutes drying time before applying a second coat of acrylic the exact same way you did the first time, except now you don't have to mess with the file or bonding agent. Stop applying acrylic after the second coat; you don't want your nails to get too thick.
Remove bumps and smooth each nail with a coarse file -- the files are usually thick and black in color. Finish up with a buffer to smooth away fine lines left by the file, and to add shine.
Wash your hands thoroughly before polishing to remove any residue or granules left over from filing.
When you go to fill in your nails, place the acrylic in the gap between the old overlay and your cuticle only and blend it in with the acrylic on the rest of your nails. There's no need to place another layer of acrylic on top of your old overlay. This will only make your nails appear too thick, so you should avoid doing it.
Any waves, bumps and indentations that you miss during the filing and buffing process will show up like a sore thumb when you polish your nails. Examine your nails from all angles to spy out all the rough spots.