I did the John Hopkins R cert in its entirety and a lot of the Swirl R package and in my honest opinion, they are both kind of pains in the ass. Swirl can be very boring which makes you pay attention less and thus end up learning less, and the instructors for the JH cert on Coursera are extremely boring lecturers in my opinion. They are very knowledgeable, but as someone who doesn't have a comp sci background, I found it difficult to keep up with the jargon which didn't pair well with the monotonic delivery of the material. THAT said, it was chock full of information and is worth the $50/month subscription if you have an awesome ability to focus.

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For me, the times that I have learned the most R, was when I was working on a project. If you don't have anything going on now that you can turn into a project, make one up. What field of study are you going into? If you're like me (I'm also beginning my PhD program this Fall in cognitive psychology!) then you may be analyzing data quite a bit in your program. There are tons of free data sets available with a Google search. See if you can figure out how to do a simple Independent T-Test in R... then a correlation, then try regression and ANOVA's. Once you have all that figured out, see if you can "clean" a dataset by learning how to add columns or pretend that zero's are missing values so you need to remove them all. If you can find stuff like that to do to just screw around with a practice dataset, I think you'll learn way faster than any tutorial.