Make bath time fun by adding toys to the bathtub. This is probably the most old school technique of making bathing fun and it might not work with every kid. Make sure the toys you add are the ones your kid loves. Ducks, superheroes, and other animals are some of the choices you have to add to the bathtub.
Add a little storytelling to the bathing time. If your kid loves stories, this is the best way to lure him/her into bathing. Get plastic story books and tell him/her stories while you are bathing him/her. Make sure you are not using these books elsewhere, as that would kill the fun of it. You need to make your kid believe that he/she will only get to listen to stories if he/she goes to the bathtub.
Add colours to the bathtub to make the foam colourful. This is one technique that works very well in drawing kids to the bathtub. You can either use food colouring or get bath colours for the bath time.
Talk to your kids about how animals bathe. This is a fun thing and most kids love it. Tell them how elephants would bathe and how would zebras bathe. If you have animal toys, you can make this process even better by demonstrating it with the toys.
Make sure the soap and shampoo is not irritating your kid. Always use mild shampoos and soap when bathing kids.