Studs provide the best, most secure place to anchor a towel bar. But when there isn't a stud where you want it to be, your towel-bar screws need a good anchor in the drywall. Forget about those cone-shaped plastic anchors often packaged with the bar; they pull out too easily. Instead, spring for some robust metal toggle anchors, which can withstand 40 pounds of pull when embedded in ½-inch drywall. So unless you plan to use the bar for chin-ups or arabesques, there's not much chance that it will ever come loose. Just follow these steps.
1. Install the anchor. Make a vertical mark where you want one end of the towel bar to be placed. Screw in the first toggle anchor at that mark until the head is flush with the wall; no starter hole is needed.
2. Attach the first towel-bar mount. Screw the bar's mounting plate (in this case a plastic bracket) into the anchor. The toggle will automatically swivel into position behind the drywall as the screw is driven in. Continue turning the screw until the toggle snugs up against the back side of the drywall.
3. Mark the other end. Hold the bar in place on the wall and make a vertical mark in line with the screw hole on the bar's other mount. Hold a level so it's in line with the first toggle; use it to position a horizontal mark across the vertical one. Drive another toggle anchor into the wall where the vertical and horizontal marks cross.
4. Complete the installation. Mark the locations of all the remaining mounting-plate screw holes and drive toggle anchors through each one. Then, drive screws through the mounts as in Step 2. Now you can hang those big, heavy, wet towels on your bar without a second's hesitation.