How Not To Live Your Life follows Don Danbury (aka "The Double D"), a perennial work-shy loser who inherits his late nan's belongings thinking he's got a massive free house, before learning she was in significant financial trouble and - much to his chagrin - he must rent out a room to have any chance of keeping up mortgage repayments. It's not all bad though, as he befriends odd ex-carer Eddie and by chance manages to get his teenage obession Abby to rent the spare room, albeit with her condescending career-driven boyfriend Karl in tow.
Don isn't very subtle or very PC, and spends much of the time speaking his mind, making dumb decisions and generally rubbing people up the wrong way in his efforts to a) earn money, b) avoid the bayliff and c) convince Abby they belong together. The script is generally pretty sharp with subtle jokes you won't notice before re-watching, and it's helped by a quirky running theme showing ways you should not approach situations (i.e., upon meeting Abby for the first time in about 13 years, handcuffing her and saying "Now this time you're not getting away"). Good scripting by creator & star Dan Clark, although it would be nice if others occasionally got some good lines too, rather than acting as buffers for Don.
There's a lot of junk on BBC3, but infrequently something decent comes out of the bag, and this is probably the best new British sitcom since the excellent Plus One.