Decide what you want to get out of learning Welsh. Is your main objective to be able to speak the language? Or is it to be able to read Welsh texts? The form of Welsh you want to learn is important, as each online course focuses on a different aspect of the language.
Determine if you want to learn the northern Welsh dialect or the southern, if you are learning the spoken language. There are many differences between the two, but in general, most Welsh speakers can understand you regardless of the dialect you learn.
Decide if you want to learn colloquial Welsh or formal Welsh, if you are learning the written language. Formal Welsh is used in medieval writings, such as the 1588 Welsh translation of the Bible. Colloquial Welsh is used more commonly in modern writing, such as newspapers, websites and business correspondence. Most online sites focus on colloquial Welsh, as it is more commonly used.
Find the right free Welsh course for you. Two great ones are the BBC series and the Nodine course. (Follow the links in Resources.) The BBC courses focus more on spoken Welsh, while the Nodine course focuses on rules of the language and the written word.
Plan your learning time. Welsh is a difficult language for English speakers to learn, as it is not entirely based on Latin. It will take several months of study for you to become conversant in Welsh. Block off time every day to go through the prior day's lesson and work on the current one. Use your Welsh when you can. Some free online Welsh courses include areas where students can practice their language skills with each other, usually via email. The more you practice, the sooner you'll learn to speak and write Welsh.