You should always hang drywall from the top down. Starting at the top makes it easier to create a straight, tight line between the ceiling and the wall. Any gaps that occur will be at the bottom, where they are easier to manage. You can either cut the bottom piece of drywall to fit the remaining space or cover the gap with baseboard trim. Additionally, starting at the top is physically easier, as you won't have to fit the top sheet into a tight space between the lower sheet and the ceiling, or try to balance the upper sheets on the lower ones while securing them.

Wet-sanding and dry-sanding each have pros and cons. Dry-sanding is less messy, so it’s a good option if you’re trying to minimize dust (for example, if you’re sanding an occupied home or working with particularly dry or dusty drywall mud). However, dry-sanding is quicker because you don’t have to keep rinsing a sponge or wait for it to dry before painting.

While not always necessary, you can glue a drywall ceiling in addition to using screws or nails. Drywall is typically secured to ceiling joists with fasteners, which is often sufficient. However, adding construction adhesive can offer benefits like preventing sagging, bridging gaps, and reducing air leaks for better energy efficiency. It may also be used for specific acoustic or insulation needs. On the other hand, many professionals advise against it because properly placed screws make the drywall structural, glue doesn't add strength, and it makes future repairs or replacements significantly more difficult. Ultimately, it's best to follow local building codes and project-specific requirements to decide if adhesive is right for your ceiling.

In many cases, installing new drywall will boost your home value. Replacing old, damaged, cracked, or wavy drywall is a great way to improve the look and feel of your home, as new drywall installed by a professional shouldn’t have any imperfections. Additionally, removing old drywall means you’ll have open walls, so you can install new insulation and address exposed issues with plumbing and electrical systems running behind the walls. All of these fixes will also add to your home’s value.