An efficient way to paint basement stairs is to paint every other stair, allowing you to stand or sit on a dry stair each time you paint one. Starting at the bottom and working your way to the top prevents you from being trapped in the basement during the drying time.
Unpainted stairs should be swept and sanded if necessary. If using a primer on bare wood, allow it to cure properly, according to label instructions, before applying the paint. When working with previously painted stairs, decide whether stripping is needed or if you can paint over the existing paint. If stripping is needed, wash the stairs, allow a sufficient drying time, scrape off any debris or loose paint and sand lightly to create a non-glossy surface.
Paint the risers first, and then paint the steps, allowing each coat to dry thoroughly before applying the next coat. Save time by painting the edging with a flat-edged brush to avoid the time-consuming application of masking tape. Keep a damp cloth handy to wipe up any drips or mistakes before drying occurs. Use a gripping additive in your paint to give the stairs a non-slip advantage, and allow the final coat to cure completely before using the stairs.