Definitely do not try to ride faster at the start. Stay at a comfortable pace. If this is an organized event, there will probably be rest stops provided. If not, stop for a snack and water refill every 15 miles or so. Be sure to drink a quart or more of water before the ride and try to empty a regular sized water bottle (20 oz.) every 10 - 15 miles. Eat a good breakfast about 2 hours before the ride starts. Snack on fruits and/or pbj sandwiches during the ride. An energy bar and/or a gel pack about midway through the ride wouldn't be a bad idea.
There are many ways to do it. Pick what feels right for you. The main thing is to stay hydrated and fueled and ride within your abilities.
Have fun.
