Total bull. Obviously it's good to do as good as you can in your first year - and the first year is all law firms can look at for vac schemes if you apply in second year. But it's much less important than second year. And much less important than final year. Most universities don't even count it - all you have to do is pass. Most people at good universities get mostly 2:2s in their first year, the results are just much lower than for the second and third years. At least at my uni, setting unrealistic expectations, i.e. working to get firsts in the first year or even all good 2:1s, is just wildly unrealistic.
My advice to first year students would be the same advice I'd give to second and third year students; work hard, review the exam papers from the beginning of the year, if your handwriting sucks; use a laptop for lectures, use a voice recorder, get an ipad and use dropbox and goodreader for reading/highlighting/annotating articles (unless you like printing thousands of pages out and are a very organised person), try to be on good terms with everyone and have friends; test each other, swap essays and try to get hints out of lecturers.
Biggest tip; don't get too worried or stressed about it all.