The Minimap Sidebar has three methods to help you improve address matching:

Geocoder Locale - By Default the sidebar uses Google's US geocoder, with address search results for US placenames overiding those of other countries, for example Toledo USA rather than Toledo Spain. If you open up the options (toolbar tools button -> Options) you can change the locale of the geocoder so that your countries placename overides, for example setting to maps.google.es will favour Toledo in Spain rather than Toledo USA.

Address Selection - If you add an ambiguous address (for example canon street), the addon will offer up a list of possible matches. Click on the one that matches your desired location the most and it will be added to your address list.

CTRL + Drag and Drop - If you are on a website that contains a list of addresses for a location, but does not actually include that location in the address (i.e a New York address website that just lists the street names and not 'New Yor' in the address as well) you can open up the options (toolber tools button -> Options) and set a default CTRL + Drag and Drop location. Now whenever you hold down the CTRL key when you drag and drop in our example New York would be added to the end of every address. Mac Users, sorry, it is a pain (and bear in mind I use a mac!?!?!), you will have to start the drag, then hold CTRL then drop.