A variety of excellent half day, full day and overnight tour packages are available from your hotel desk or any of the numerous travel agents and tour operators which abound in Bali. Or you can find a car and driver who will also act as your guide. Competition is tight and many drivers know several languages. Tell the driver your desired route and negotiate a fee. Ceremonial processions often overtake the whole road so if you're caught behind a procession, enjoy the colorful experience.
Roads can be quite narrow with heavy pedestrian traffic on each side.
Walking is still one of the best ways to see Bali. You'll be close to the action. Don't forget a sun hat and bottle of water. If you're walking in Kuta be wary of the undulating footpaths and open access holes placed every metro or so in the footpath. Every so often, the access holes are left open or the lid is broken, which can result in a nasty fall especially at night.