Glue / Nail Polish Aglet
Soaking the shoelace end either with general purpose glue or with several coats of nail polish produces a more durable aglet.
Squeeze a small amount of either glue or nail polish onto the end of the shoelace. While this is drying, squeeze and
twist the end to both reduce the thickness of the tip and to aid glue penetration.
When completely dry, trim any rough ends, then add another coating of either glue or nail polish for a smoother, longer
What Sort of Glue?
Preferably choose a glue with an acetone-based solvent, such as "Tarzan's Grip", "Elmer's Clear Household Cement" or "Britfix Balsa Cement", just to name a few. These will dry clear, hard and waterproof, as opposed to the PVA based glues such as "Aquadhere" or "Elmer's Glue-All", which are not as hard and are only water resistant. You can tell the difference by their look and smell – acetone based glues are clear and have a strong petro-chemical smell, whereas PVA glues are milky white and smell mildly acetic.
NOTE: Glue manufacturers have health warnings against "prolonged skin exposure" to the above acetone-based glues, so wear gloves if this is of concern (or if you hate sticky fingers). Use acetone, thinners or nail polish remover to clean up afterwards.
Clear nail polish is a perfect substitute for glue, while colored nail polish can be used to add either a complementary or contrasting color. Nail polish with glitter can be used to add some sparkle.
Liquid Electrical Tape
It has also been suggested by several visitors to use "Liquid Electrical Tape" instead of glue, though I haven't tried this myself. Liquid Electrical Tape comes in either a tube or a tin with an applicator brush. It forms a smooth, opaque, slightly flexible aglet.