University rankings might have their uses but they're mostly a joke.

The rankings can change wildly from year to year, A lot of the universities have very similar scores (so the rankings don't mean much), and some of the criteria they use is either irrelevant to 90% of undergraduates, unreliable, or a bit meaningless.

Most importantly, what you get out of your course is entirely up to you. There's nothing magical going on at highly ranked universities. They're not going to do the work for you.

And in the end, nobody but you cares what your university was ranked in 2017. You might be able to go, "Keele ranked better than Manchester," but ultimately most people know Manchester is an enormous and hugely respected university.

Look at how your subject is ranked to get an idea of what different universities might specialise in and then just look at what the course actually offers. Do you like the sound of the modules? Are they going to give you a chance for practical experience? How much is a pint at the student's union?