There is a lot of information already on the web about adding data to OpenStreetMap, which is frequently being improved, so it is easier here to provide pointers to it rather than try to explain it here. The fundamental rule is that you must not rely in any way on copyrighted data when you make additions to OpenStreetMap. Instead you can:
- from a computer, trace features, such as over out of copyright (more than 50 years old) Ordnance Survey maps or unrestricted satellite imagery, both of which are provided in free mapping tools, such as Potlach 2 (see below)
- when you're out and about, take a GPS trace or mark particular points, whether shops or waymarkers on a path, using a free app on a GPS smartphone
- or combining both, by printing out a section of OpenStreetMap and then mark missing street names or points of interest when you’re out and about. These can then be added to the map at another time or by other people, just remember to write neatly. This can be a good way of involving volunteers who don’t feel comfortable adding data to the map using a computer.
A very good start is the new Get mapping guide, produced to encourage people in Scotland to map cycle routes. If you need more information, the OpenStreetMap wiki is quite comprehensive. The beginner’s guide, which is highlighted on the front page of the wiki is worth looking at first.
If you are able to use a basic graphics program, you will find adding data relatively easy using Potlach 2, an on-line editor tool accessible from OpenStreetMap by clicking on the edit button. There are also how-to videos linked from inside Potlach 2.