Acknowledge your situation. Your mind is your best tool. A positive mental attitude will go much further than the best gear. Accept the situation and be ready to click into action.
Take inventory. Once everyone is out of harm's way if an accident is the cause of your situation, do an inventory of yourself and group for injuries and treat accordingly (knowing first aid in advance is just smart outdoorsmanship). Once injuries are addressed, look around for anything that can be used to complete other steps - to build a shelter, to fuel a fire, to collect water - anything and everything is important.
Build a shelter. You've got to stay warm and dry. Building a shelter should be started as soon as you can. You can always improve on it later, but get out of the wind or rain as soon as possible. If there are enough members in your group, starting a fire is fine, but if you put all your effort into it and the rains come, you have just increased your odds for things to get worse.
Be ready to signal. In some cases, it might be hours or possibly days before someone even knows you are missing. However, in other cases they may find out right away. Sometimes you may even know of certain scheduled traffic that will be passing over or through your area.
The best signal is one that is in stark contrast to its surroundings and background. Dark smoke by day, bright lights by night are two common forms of signaling. There are many more options, too. Consider a bright flag to wave when you are selecting clothing or tarps or other gear that could be used to attract attention.
Drink Water! After three days, lack of water can become a real problem for the average human. Water can be collected from many sources including, of course, ponds and streams. The danger is the little critters that inhabit the water. Boiling kills off the bad guys, but not toxins and other contaminates. You can collect rainwater that runs off your tarp. Be advised, if you have a lot of food, but little water, go easy on the food. Your body requires a lot of water to digest things. You can go for several weeks without food.
Find Fuel Food. Despite the concerns about water mentioned above, the body needs fuel and it's important to learn what is edible in the wild. Remember, however, that just because something is safe and edible, it doesn't mean it's going to taste good. And most importantly: if you don't know what something is - if it really is edible - don't eat it.
In many areas of the country, classes are offered that teach the edibles of the region. It's a class worth taking, not only for the precautionary measures, but also for the joy of learning some new and often exotic flavors.
"Play." Remember Step 1: keeping a positive attitude? Making some of these tasks into games, even drawing a tic-tac-toe grid in the dirt, can help ease the tension of a survival situation. Keep your brain alert.
These are fundamental techniques that can be practiced during regular outings. Practice your outdoor skills regularly, use your head, and hopefully you never have to rely on these seven steps.