When a go out for anything I use to take pics, and write some comments to help other users. This may be really useful before attending that site. Also I add new businesses, shops, advice them about promoting and posting their businesses to make a better profit and visibility. Many people look at me thinking that I am crazy to make pics to anything. Also, about restaurants I post pics and make advices. Sometimes I add new spots for outdoor sports such as entrances or exits to a park, river, that nobody knows that they exist. I promote everything I can. Also by adding a bridge rencently builded that cross a small river.
That is actually the goal. You want to connect with what regular people want to know about. Anyone can take pictures of famous landmarks, but people really want to know where a local mom and pop joint that has local food is located. That is what google maps really shines at.