Using pictures for surveying shops is pretty efficient for collecting data. You probably want quite large images (perhaps larger than Mapillary shows) ideally taken orthogonal to the shops. It’s quite hard to interpret photos taken talking along the street because certain cues are missing.
Be warned though, adding the data can take considerably longer.
For collecting other information Field Papers can also be useful, although I find juggling pen/paper, mobile phone & camera a bit too much sometimes. Audio notes (which can be added using things like Vespucci or OSM Tracker) can also be helpful.
If using photos etc, it often helps to map the buildings up-front: providing you have adequate imagery. When taking photos it helps to ensure some included the roofline. Location of chimney stacks can be very helpful to get POIs in the right place.
My experience is that I can get round a decent sized town centre in around 90 minutes, but then I have a weeks worth of editing to do. Admittedly a big factor here is that I use OpenData to add addresses and other information.
It depends on what’s important to you. Is it important to have all bus stops mapped, or is it important to know the opening times of points of interest?
For most points of interest you’ll usually want to be on foot so you can check missing data (like opening hours and contact information), but if you’re mapping road infrastructure (speed limits, lanes, surface, bus stops, road services), it might be easier/faster to drive and perform audio mapping or video mapping, or to simply collect tracklogs if you’re running short on memory. Or you could contribute to Mapillary and have some friends help transform that into OSM data.
I live in a place where there’s a lot of “basic” data still missing, so I usually do car trips and tracklogs/audio mapping, but some areas are interesting/complicated enough that I stop and do some walk surveying.
I also maintain a “todo” JOSM layer for myself where I keep issues that I encounter over time (usually data that doesn’t match imagery, strategic information reported by questionable sources, or what appear to be mistakes made by other mappers), then periodically I plan a journey to inspect the problematic areas.