Quarter Round Video
Using toe strip will hide that gap caused by uneven flooring. The quarter round molding is flexible enough to follow the floor contour. What do you do when you get to a corner? You can use your miter saw to cut both pieces to a 45 degree angle and slide them together. This works if your corner is square.
If you have a corner that is slightly out of square, use a coping saw and cut the one piece of the molding to match the curve of the other. Once put together, it will look just like a mitered joint.
When nailing the toe strip or quarter round, use long nails. They will reach through the drywall, the floor molding and into the wall base plate.
One last tip, at the door, cut the toe molding at a 22-1/2 degree angle for a better look.