As with anything else worthwhile, a home wallpapering project requires planning and forethought. Take the time to equip yourself with the right tools, and use the right tool for the right job. If you plan to add a wallpaper border to a painted wall, you will first need to ensure that the wall is surfaced properly. Assuming that you have a relatively smooth wall, painted or wallpapered, choose a border that complements the main design of your room.
The tools you will need for hanging wallpaper border are similar to those used to hang wallpaper. A sponge, putty knife, seam roller, smoothing spatula, razor knife (with refill blades), and extra adhesive are your main requirements. With the wallpaper border glue activated by soaking the border roll in the paper tray, affix the border starting in the least visible corner of the room, perhaps over a door, or in the darkest (shadowed) corner. Using a dull razor knife will result in ripping the wet wallpaper border paper, rather than slicing through it. Where wallpaper border tends to peel at corners and around edges, a dab of extra adhesive will keep it laying flat, affixed to the wall. If you have never applied wallpaper or borders before, home improvement stores offer workshops and free (or inexpensive) training where you can practice applying border on a small scale.
Happy border hanging!