I'd agree with the suggestion to look like tourists. Better for you, and better for the hundreds of thousands of bikes around you!
Your first time riding in the central part of Amsterdam can be overwhelming and seem chaotic. But there are definite rules of the road, and newcomers usually break a lot of those without meaning to. As another poster noted, a tourist bike lets people know to expect.
For riding around the city of Amsterdam and short trips into the countryside (Haarlem makes a great day trip) I've had good experiences with "Yellow Bike". And yes, the bikes are bright yellow.http://www.yellowbike.nl/en/
Central Amsterdam is so compact that you might also consider walking and trams in addition to biking. The advantage of walking is that you can stop and look around you. Some days you may want to just walk, other days the bike (especially to the Vondelpark) will be a great option. Even walking you want to be aware of the bike lanes, usually colored red... backing up to take a photo can lead to trouble if you stray into bike traffic.
For longer trips out into the Netherlands and beyond I take my own bike across, but for a companion's bike I had an excellent experience with Tulip Cycling. (some folks may recall an article about them in Adventure Cycling a few years back.) I would not suggest using one of their bikes in the city of Amsterdam, though. If I were them, I wouldn't even want to rent a bike for that use.http://www.tulipcycling.com/
Enjoy your trip! The Netherlands is bicycling heaven.
p.s. For a real feast, try the Celebres Risjtafel at Sampurnahttp://www.sampurna.com/index.html