It is said the the hardest part of the workout is putting your shoes on !!
It is a good idea to set a plan of attack ( for your exercise program that is ) by planning your week in advance allocating time with work, rest, play and exercise. For the exercise part allocate a time (3 or 4 times per week or more) and a place (even if if its a mat in the back room). The main thing is to get started ! If necessary ease into your workout and as you warm up to the task at hand you will find generally you will workout more than you expected but at worst you can give yourself some brownie points for taking the first step which will build to your objective and you will also be developing a (good) habit.
Goal setting. What path are you taking ? treadmill, spin bike or weights. It`s good to set some long term goals and aim high but to get there you also need short term goals. Very short goals maybe to put your shoes on ( prepare for the workout ), leave your clothes or equipment in an obvious place the night before (as a reminder for your weekly allocated training time), start with a short session but Just get started !
Maybe plan a workout based on time eg 20 minutes to start (after warm up ) alternatively have a series of exercises and have repeat sets as you get fitter increase the sets and weights. If it`s time based increase the intensity in that time frame than increase the time allocated and repeat.
Start easy and get through your predetermined exercises and as you improve increase your reps, weight and or time frame for exercise. Record your efforts. By recording your efforts you can track your progress and develop your program.