Learn to speak some commonly-used phrases in Tulu. The Mangalore website has a list of some everyday phrases in Tulu. Tulu can be transliterated into English, so learning to produce the language orally is a good way to start actually using Tulu.
Study the Tulu script at the Shivalli Brahmins website. This site contains a discussion of the script's origins and an image of the script.
Study the structure of the language and its grammar from example sentences that have been translated into English on Ourkarnataka.com. Many Tulu lessons are available on this site. Note, however, that the first 12 lessons are only available in the Kannadu language.
Listen to Tulu as much as possible online. Tulu videos are available for free on YouTube. Search for "Tulu" to find videos. Listen for words you know, as well as for words you do not to build your vocabulary. Note the context in which you hear a new word so that you can try to deduce its meaning on your own without consulting a native Tulu speaker or a dictionary.