What are the best methods for applying bath tub sealer to ensure a watertight seal and prevent leaks?

The best methods for applying bathtub sealer to ensure a watertight seal and prevent leaks are to thoroughly clean and dry the surface before applying the sealer, use a high-quality silicone-based sealer, apply the sealer in a continuous and even bead along the joint, and smooth out the sealant with a tool or your finger for a neat finish.