What is the best method for applying grout or caulk around a tub to ensure a watertight seal and prevent leaks?

The best method for applying grout or caulk around a tub to ensure a watertight seal and prevent leaks is to first clean and dry the area thoroughly. Then, apply the grout or caulk in a continuous and even bead along the joint between the tub and the wall. Use a caulk gun for precise application and smooth the bead with a wet finger or caulk tool. Allow it to dry completely before using the tub.