I have taken quite a few MOOCs since they were originally started by George Siemens and Steven Downes in 2008. With them I took Connectivism and Connective Knowledge (2008) and Personal Learning Environments, Networks and Knowledge (2010)
Now MOOCS are mostly run by organizations such as Coursera, Edx and Udacity. Through Coursera I took Video Games and Learning (2013), Understanding Video Games (2014) and am presently taking Emerging Trends & Technology in the Virtual k-12 Classroom (2015). Through Edx I took Design and Development of Educational Technology (2014).
On the basis of these experiences I have come up with some tips for participating that I plan to employ in all future MOOCS and which may be useful to others as well.
1. Read through the syllabus carefully to see what parts are going to be of interest to you. You don't have to do all the assignments. Be picky and devote time to those activities that will be a good use of your limited time.
2. Write a detailed introduction in the discussion forums so that others with similar interests can find you. You can often make very valuable connections with people in these forums.
3. Read and contribute to discussions. You learn by putting your thoughts in written form. You can also learn and grow from the responses that others write to your posts. In addition, your own learning or teaching experiences may be really be valuable to others, so be sure to post some replies to what others post.
On of the best aspects of MOOCS if not taken for credit or certificates of achievement is that you get to choose your own level of participation. So how much you learn is up to you!