There really is no secret to becoming FIT! Here are the things I do everyday of my life.
Weightlifting: Lift weights 3 times a week. Focus on then big lifts: Deadlift, Squat, Press, Cleans, Jerks, & Snatches. Focus on the functional and gymnastic accessories: pull-ups, dips, push-ups, muscle-ups, box-jumps, & kettlebell swings.
Conditioning: Sprint, carry, run long distance sometimes, row, swim, yoga, bike, & play sports.
Follow a program and listen to your body: Train it hard almost every time you step foot in the gym. Those with specific goals should follow a legitimate program focused on that specialty. A general Crossfit program can do wonders for 99% of you and also serve as GPP compliment to any sport-focused program.
Make sure you rest: Everyone should have at least one full rest day, some need more. For those that hate being inactive, you can spend time on active recovery: do some yoga, walk, hike, and do other outdoor low-intensity physical activity. Remember that you must take rest at some point.
Eat a clean diet: Lots of quality protein and fat. Tend to stay lower carb consisting of starchy veggies, some fruit, and sweet potatoes. Athletes can use higher carbs as activity level will demand.
Manage lifestyle factors: sleep, stress, & recovery