Going on a bike tour for the first time can be a lot of fun, but it's easy to overdo it or underprepare. If you want to really enjoy your first trip, follow the tour company's instructions for preparation as closely as you can, and address these three issues as well. They'll help you adjust what you need to take so that your trip doesn't put too much physical strain on you.
Test Your Storage
Depending on the length of the trip, you'll need several different storage packs with you. You won't want a backpack because the weight can tire you out prematurely, but a front pack, rear rack, water bottle holder, and side panniers -- bags that hang off the sides of the rear rack -- usually work for short to moderate trips. Anything longer or more intense than that often requires a bike trailer.
The problem with the storage is twofold. One is that you might pack too much, making your bike very heavy and harder to move. The other is that the storage, particularly the trailer, can throw off the bike's balance and center of gravity.
Always test-ride your bike with the storage packed. Change the type of storage if necessary; for example, a bike trailer that connects very high up on the bike might be awkward, but one with a lower connection might work fine.
Skivvy Rolls and Other Efficient Packing
Pack as efficiently as possible. Use skivvy roll packing techniques to keep clothing together so items don't pop out when you try to remove something, and squeeze out as much excess air as possible. The more compact your packing, the neater everything will be, too.
Plan Your Food Carefully
Please, please, plan your food carefully. Look at what restaurants and grocery stores might be along your chosen route if the tour takes you through towns; pack healthy foods for trips that are in the wilderness. Don't rely on junk food to give you energy because it can weigh you down. Some trail mix, sure, but that fast food at the end of the day isn't going to do you much good other than provide calories.
Talk to the people leading the bike tour to get a sense of whether your planned packing is in line with what you really need. The tour guides should also be able to give you more tips for packing appropriately. You can also contact companies like Bootdoctors.