Have a quick look at a map before you read this so the road names make some sense!
Walking round the harbourside is nice if the weather is ok, as others have said, get to the Arnofini bar/arts venue, cross the bridge to the M Shed (well worth a visit), past the old cranes and then basically keep the water on your right....
however, its worth a wander round Clifton too for the indy shops et al, lunch in the Avon Gorge hotel is nice if its dry too as it has a big patio overlooking the river/bridge. So follow the loop as above but once outof the boatbuilders yard, carry on walking with the pumphouse pub on your right and stay on the main road, follow it round to the right then turn left up a steep hill called Ambra Vale, keep walking up, up a bit more and you will eventually reach Regent Street, turn left and you are in Clifton village.
From Clifton, the number 8 or 9 bus is your friend which will take you right back into the centre or all the way to temple meads. I'd walk it myself from the top of Whiteladies Road all the way down Park Street back to the centre.
The Watershed does good food and beers although it can be busy. Its on the waterfront unsurprisingly. Boston Tea Party have two cafes, one on Whiteladies, one on Park Street, their raspberry and chocolate flapjack is awesome!