Did it all about 4 years ago. Daughter just graduated. Your eldest will probably have an idea of the type of Uni they'll be aiming for...Oxbridge, Russell Group or something else...and from there what appeals...big city, traditional, red brick, campus uni etc. So they'll select some possibilities based on these preferences. When visiting, I think it's then a case of getting a 'feel' for each sepecific institution. You can learn all the stuff about academic performance and facilities etc from afar. Visiting is all about deciding whether it's somewhere you feel you can be happy studying (and everything else) for three years.