The ideal mapping approach involves having tools that let you record new features (e.g., GPS and some kind of note taking device such as pen and paper) and also let you see what has already been mapped in your survey area (e.g., Walking Papers).
I prefer to use as little paper as possible, so when I discovered this solution that works for GPS-enabled iPad or iPhone devices, I wanted to share it.
You will need to download GaiaGPS (http://www.gaiagps.com/) from the iTunes App Store. Once you have installed the application, you can download the current OSM maptiles for the area you want to survey and then you can go into the field and start your work. As you start your surveying, you can place pins (aka Waypoints) and label them with notes relevant to the feature you are capturing. If find labelling/annotating waypoints in GaiaGPS orders of magnitude easier than trying to do the same thing with a standard GPS unit. You may also want to consider turning on a track (GaiaGPS calls it a "trip") so that you can get the path of your survey for later upload to OSM.
Once you have finished your survey, you can get the .gpx data out of GaiaGPS by e-mailing it to yourself. Once on your desktop, you can import the .gpx data with annotated waypoints and tracks into a tool like JOSM to guide you in adding OSM features.
Here is a 5 minute video that demonstrates the key points. The video quality is mediocre but you should get the idea of how to use the tool. I am not a representative of TrailBehind (the makers of GaiaGPS). I am only a very satisfied customer that has learned to use this app to simplify my OSM surveys.