I tried adding a supermarket, which I visited last night. Successfully added and found to be auto-merged with another supermarket nearby. Tried 2 more times and same happened.
I highly recommend to add places with simplest correct name and complete other info. For example the phone number of two places are definitely different. Also this may be applicable about the working hours. So if you try to add it with phone number, working hours and also accurate address (using # to add building number) which is different with other store, there is less chance for auto-merge.
Seen that too several times - add new place with photo - approved - next I look the place I added is not there and my photo is associated with a different - wrong - place in the neighborhood.