In most cities/towns that grow organically (ie. not New York, Phoenix, or Gainesville), street names happened as a result of local flavor. You wouldn't tell someone to head down peach pie lane and turn left on pecan avenue. You'd tell them to head down the elm street* and turn left at the street just past the Horse and Crown (so named because the sign outside has a horse and a crown painted on).
If you want good names for streets and alleys, decide on what businesses, churches, architecture, and geography you have there. If you name something Canal St, it probably ought to run along side a canal... if it isn't a canal itself! If you have a broad street capable of handling a lot of traffic, why then that's obviously Broadway. If you have a street running alongside a large park maintained at the city's expense, you've got yourself a Park Place, if not a Parkway. And if you've got a St. Mary's church next to a creek (aka "bourne"), then you've got
Marylebone Street.
I'm a big fan of giving worlds real medieval flavor and realism, rather than just trying to make them dirty and fantasyish.
For example, if you've a hill in the middle of your city, that's where the nobility will live. Medieval towns lacked true sewer systems, so a common method of getting rid of sewage was to toss it in the street. The streets were sloped so that the center of the street acted as a gutter to carry sewage away to, at the best, natural waterways that acted as sewage systems (for example, the covered waterways of London's
River Fleet. This led to quite a stench, a palpable miasma. The nobles rose above it and, of course, their filth flowed quickly downhill. Also, they were the ones who could afford to have water carried uphill to their homes or, later, install expensive pumps/wells that had tunnel through a great deal of solid earth to get to water.
Where people live, how places are named.... only in a planned modern city are such things truly accidental. When a place is organic and has a history, there's always a reason, even if it's not apparent.
By the by, sometimes the reason is stupid (laws). And sometimes it's very counterintuitive. Why are ancient temples in the middle of depressions? Because cities tend to move toward the sky. People drop their filth near their homes, the ground rises, they build new homes; only temples are kept clean and maintained and, after many generations, end up in mini-valleys. The Parthenon, having been built on a rocky hill in the first place, is an obvious exception.
* so named because it had a ton of elms. There are more Elm St.s in the US than Main St.s because elm trees grow 3-5 feet a year; instant air-conditioning.