First, you need to be fit enough for the trip requirements. IMR offers relatively easy outings such as 'A' trips to challenging 'D' trips. Know your limits and ask your Trip Leader questions if you are in doubt?before you sign up for the trip! Refer to IMR Trip Classifications for more information.
Second, participants should be prepared with Trip Essentials. Your Trip Leader will probably ask you some questions about your fitness level (depending on the trip classification) but perhaps also tell you extra things to bring. For longer day trips, you should carry some simple Trip Essentials (check out IMR Trip Essentials - What to Bring for some insight). Our philosophy is that prepared hikers are safe ones. Even if you don't end up needing that First Aid kit on your big hike, someone else on the trail might. And you might make the difference between some injured person having an uncomfortable day versus a disastrous day.
Third, we ask that you understand that your Trip Leader has volunteered their time to share their anticipated trip with you and several others. Trip Leaders have a destination/goal they have planned for and the entire group is now a team. We ask that participants respect the plan if you wish to explore another side trail or peak, then we encourage you to plan a trip separately from your Leader's activity. The Leader determines what the team will do, but may take input from participants too. For example, if someone is having a bad day, the Leader will try to be in tune to this and people are not left behind alone. This means the Leader may ask for a couple volunteers to remain with that person for safety reasons. If the weather turns bad suddenly, the Leader may decide to turn around and the entire group will need to do so for their safety. Suffice to say, the Leader may need to make an unpopular decision, even if the group is near their intended goal and we expect participants to respect this. Who knows? You may feel fine today, but you will appreciate the fact that Leaders do their best to ensure safety of the entire group if you are injured or having a bad day the next time.
Fourth, if you are carpooling, be prepared to give some money to the vehicle owner. IMR asks that non-drivers provide the driver/vehicle owner with a reasonable amount of money to cover fuel and other vehicle costs (we also ask vehicle owners to not be greedy). Car-pooling is an important element in IMR activities, since many TH?s have room for only a few vehicles, and it is silly to have everyone drive separately.
Fifth, be positive and flexible. Trips sometimes don't turn out as planned, even with the best preparation. When participants are flexible, it will help everyone enjoy the trip even more when adjustments need to be made due to trail conditions, weather, injury, etc. But good preparation often allows people to have more options and in the backcountry that's a great thing!