Smaller cracks in drywall can actually be more difficult to repair then larger cracks that you can mud and tape but there is a way that you can get decent results that will last for years.
The first thing you need to do is inspect the crack and note its location.
If the crack in your drywall is over a doorway or over a window then you could have a structural problem with your house. If your house is new this could be due to settling of your wood framing and foundation. If you have an older home and the cracks appear after water damage to your foundation you may need to take closer notice.
The size of the drywall crack is important.
Small cracks thinner then a dime that run a few feet are not that much of a problem and show the force that home settling can have on drywall by pulling it apart.
If you have cracks that vary in size and at any point are larger then a half inch wide then you most likely have a structural problem that needs to be inspected. Structural problems can be from a rotted sill plate at the base of a wall, foundation problems, even termite damage. They could also be from locating something too heavy in the area such as a safe or whirlpool bath.
And remember that cracks can be caused from problems below or above the room you are in.
Using Latex Caulk to Fill Small Drywall Cracks
To fill small cracks you need something that is liquid enough to penetrate the crack but drys to a finish that can be painted.
The easiest material is a 100% latex caulk and this type of caulk just so happens to be the least expensive too.
You will need to use a small rubber spatula to force the caulk into the crack.
First apply a bead to the crack then using a crosshatch pattern work the caulk into the crack. You don’t want to run along the crack or straight against it or you will pull caulk out of the crack rather then force it in.
After the caulk has had about 5 minutes to setup use a damp not wet paper towel and remove any excess caulk from around the crack without actually going over the crack its self.
Painted surfaces especially ones that have paint applied by a roller have a texture so it is important to remove the extra caulk the best you can so the texture will remain.
Painting the Wall Surface
It it best to wait a full 24 hours before you paint your wall. This will allow the caulk to cure. However if you are in the stage of preparation or trying to hide it before guests come… you can probably go over it with a single coat of latex paint on a small roller.
If you are prepping a whole room then try to do this the day before or at least 4 hours before you expect to apply a primer or top coat of paint.