Hi Bellionaire and welcome
University of Latvia is a great choice.. I'm sure you'll have lots of fun in Riga!
A lot depends on your budget, but assuming your looking at either a studio or apartment share, I would recommend looking along the major tram routes and identify all the districts and compare for convenience and price. As a student you will get a reduced price travel pass, so that will make it easy.
I lived in Terbatas iela for a year (near the junction with Talinas iela) and this worked for me. There is a great market on Terbatas where you can buy all your fresh produce from local farmers and sellers.
Then you have the old town which might suit you if you a party type, although the prices there are for tourists.
SS.lv is the site I always used to find accommodation, zip.lv has some also, then you have the agents like rentinriga.com etc.
Best advice is to get a local to make the phone calls for you, to haggle over things like the agent commission, and to check on things like estimated heating bills, is internet included etc.
Prices are all over the place as you would expect, but expecting to pay 150lats + bills for a flat share would be reasonable. Cheaper if you are prepared to live in a block housing district or further out.
Scott