Here are the simple steps to getting really fit fast (in a nutshell):
1. Get ultra-motivated and focused on consistently doing what it takes to get fit and lose weight quickly.
2. Eat a diet based around lean meats, fish and seafood, eggs, vegetables and raw fruits, nuts and seeds, beans and legumes, few starches, and no processed/refined sugars, flours, or fats. Learn how to cycle your intake of starchy carbs (rice, potatoes, grain products, etc.) for best results. Have an occasional "cheat" day (every 2 weeks or so) to give yourself a break/reward.
3. Do short, intense full-body strength training workouts along with high-intensity interval training (HIIT) cardio exercise. Focus on compound, multi-joint, bodyweight-only exercises. Be creative and change up your workouts often to keep your body from adapting. Find a sport you enjoy and play it often. Exercise 3-6 times per week, with at least one full rest day. Keep things fun and interesting!
4. Take supplements that are proven to work: whey protein powder, omega 3 fats, quality multivitamins. If you want, find a good caffeine-based fat-burner/energy-booster supplement and take it before workouts to increase fat-burning.
There you go: everything you need to know to get fit, lose fat, and create a healthier, great-looking body fast!