Set your goals! Start with short term to build into long range results. Base your exercise on Honest and Real expectations, note I never said "achievable", trust me....you have no idea how much you will achieve....yet!
Remember real goals, if you're a bit on the skinny side, you will have to enter a world of dedication and discipline if you want to look like Arnie. Same same if you're a bit bigger boned like Pavorotti and want to look like Brad Pitt in Fight Club!