Most press-on sets that fail within a day were applied to a nail that still had oil on it. The application itself takes ten minutes; the difference between a set that lasts two days and one that lasts two weeks is almost entirely in the two minutes before you attach anything.
Step one: prep
Push the cuticles back with a wooden stick — do not cut them. Lightly buff the surface of each nail with a buffer block, just enough to remove the shine. You are not thinning the nail; you are removing the smooth layer that adhesive cannot grip. Then wipe every nail with a prep pad and wait until it is completely dry. If you have just showered, wait twenty minutes.
Step two: size every nail before you glue anything
Lay out the sizes first. Match the widest point of the tip to the widest point of your nail. The correct tip spans your nail side to side with no skin visible and no overhang. If you are between two sizes, take the smaller one. A slightly narrow tip looks like a natural nail; an overhanging tip lifts at the corner and reads as fake from across the room.
Step three: attach
For two to four days, press an adhesive tab onto the nail, then bring the tip down at a forty-five degree angle from the cuticle and press for fifteen seconds. For up to two weeks, use a thin line of glue at the base and down the centre — never a full flood. Glue that squeezes out at the sides is what makes removal difficult and messy.
Step four: finish
File the free edge flat if the tip is longer than you want. Keep water off them for an hour. After that, treat them as you would your own nails: gloves for washing up, and no using them to open things.
The mistake that causes most early failures
Attaching from the tip end instead of the cuticle end. Pressing the tip down flat traps air at the base, and the base is where lifting starts. Cuticle first, always, at an angle.
Removing them without damage
Soak in warm soapy water for ten minutes and work the tip loose from the side with the wooden stick. Never pry or rip a tip off dry — that is what removes surface layers and leaves nails looking worse than before you started. Full steps are on the how to apply page, and sizing is covered in the size guide.