Clean the edges of the glass of any powders, or dust from grinding and oils from handling to ensure the foil sticks tightly to the glass. You do not have to be particularly careful about marks on the surface of the glass.
Keep your hands dry and clean while foiling, as oil or moisture on your hands will prevent the foil from sticking to the glass.
Start foiling on a straight length of glass. If the glass is only curves, begin the foiling on an outside curve. If the end of the foil wrap doesn't meet perfectly with the beginning, you can trim off the uneven overlap with a sharp craft knife. Only light pressure is required to trim the foil. Be careful not to scratch the glass, which can happen if your blade is dull, or you apply too much pressure.
To centre the foil on the edge of the glass, hold the piece vertically and look on both sides of the glass while you apply foil to the bottom edge with the sticky side of the foil facing you. This enables you to judge the evenness of the application. It may take a bit of practice to look down both sides of the glass as it requires overcoming the habit of using the dominant eye. To practice, you can look down the side that matches your less dominant eye and judge the amount of foil that overlaps the edge. You can switch your concentration from side to side to determine the equalness of the foil overlap on each side.
Burnishing the foil onto the edges and then on the upper and lower surface with a fid will help the foil adhere firmly to the glass throughout the soldering.