For QGIS 2.2.0-Valmiera, how does one increase the label size of OpenStreetMap layer or any other basemap layer? Presently the labels are way too small to read. For example, I find that for the same zoom level of a map in www.openstreetmap.com vs the same map in QGIS2.2, the map in QGIS2.2 has labels much smaller than the one from www.openstreetmap.com. For illustration, click here: https://drive.google.com/file/d/0B27Gf4KIu-6-NFVhSV9zUFBDZGM/edit?usp=sharing
Alternatively to the Openlayers plugin, you can call the OpenStreetmap tiles by a TMS service as described here: (Page not available per Feb 2021)
The disadvantage is that the tiles only look good in the native resolution (as listed in the article), and other scales look a bit weird.
You can use the TileMapScale Plugin to snap the scale to the optimal display of tiles: (Plugin not available for QGIS > 3.0 )
You have to fetch the zip from https://github.com/datalyze-solutions/TileMapScaleLevels and expand it manually to your .qgis2/python/plugins folder.