I had this in the osmly readme, too detailed, will scare people away.

flow.md

Current flow

• WARNING: make sure everything is approved by the appropriate OSM authorities like the imports mailing list before importing to the main OSM API, if you aren't sure, ask somebody
  • further details on the OSM wiki
• prep the source
  • remove conflicting duplicates
  • reproject to EPSG:4326 (WGS 84)
  • remove useless attributes (like official internal ids)
    • OSMLY can do this for you, see usePropertyAsTag setting in settings_documentation.md it takes a whitelist of properties you want to use, everything else is ignored
  • rename attributes to their osm equivalents
    • OSMLY can do this for you, see renameProperty setting in settings_documentation.md
  • add any needed common attribute like 'source=cityXYZ' or 'leisure=park'
    • OSMLY can also do this for you, see appendTag setting in settings_documentation.md
• convert your source to geojson
  • I suggest ogr2ogr or QGIS
    • ogr2ogr geojson details
    • example ogr2ogr: ogr2ogr -f "GeoJSON" -simplify 0.0001 -t_srs "EPSG:4326" -sql "SELECT NAME as name from parks" -progress parks.geojson parks.shp
• run python build.py YOURGEOJSON
  • this makes sure geometry is valid, simplifies, seperates easy and difficult items, adds bounds, and converts everything to a sqlite database ready to be served up to the world