What are the best tips for selecting and applying tile grout filler for a professional finish?

When selecting and applying tile grout filler for a professional finish, consider these tips: Choose the right color and type of grout for your tiles, ensure the tiles are clean and dry before applying the grout, mix the grout to the right consistency, apply the grout evenly and press it into the spaces between the tiles, wipe off excess grout with a damp sponge, and seal the grout once it has dried to protect it from stains and moisture.