Let's start with this very important rule: NEVER OVERDO THE FIRST FEW SESSIONS. Many beginners to exercising fall for this trap, especially when they do not have qualified trainers with them. They get overly excited and lose patience. They try to produce in two weeks what often takes years to accomplish.

They begin by going all out right from the start doing as much as they can. The next day, their joints and muscles lock up in pain. Then, they get discouraged, stop exercising for a while and give it up altogether. Workouts should start out smooth and easy.

Here is a warm-up routine to do 1 set of before every workout, but doing 3 sets of these alone can be a pretty good workout; particularly if you are a beginner.

LEG STRETCH
Lean over deeply on your left foot while your right leg is stretched out to your right side. Maintain balance.
Slowly, raise yourself with your left leg to a standing position.
As you stand, spread your feet wide apart.
Repeat this for ten counts.
Do steps 1 to 4 again; this time, alternate the legs' position (left becomes right, and vice-versa).
This exercise warms up your legs, calves, and abdomen.

LEG SQUAT
Stand erect, chest out, with your buttocks protruding and your stomach in. Put your hands straight out in front of you. Relax.
Do squats by bending your legs to lower your body. Bend your legs until your upper legs (thighs) are parallel to the ground and you are in a squatting position. Keep your body erect as you squat.
Then raise yourself as you straighten your legs back to a standing position.
Do around 5 to 10 squats. Inhale deeply as you go down. Exhale as you stand up.
This exercise warms up your leg muscles, calves, and the muscles in your abdomen.

TRUNK TWIST
Stand with your feet about 3 feet apart. Relax.
Place your hands behind your head with your elbows out to the sides.
Very slowly, twist your body to your right without moving your legs or feet. Try to twist to your right as far as possible. Your face and body should be facing your right side while your legs remain steady. Then hold on to this position for 10 seconds.
Do the same to your left side.
This exercise warms up your legs, back muscles, and abdomen.

ARM ROTATION
Stretch out your arms to your sides. Keep them level with your shoulders.
Simultaneously rotate both arms to the front. Do this 20 times each rotation.
This exercises your shoulders, arms, and back muscles.

ARMS PRESS
Bring your right and left palms together. Have all fingers and palms pressing each other in front of you while pointing the fingers upwards.
Simultaneously push one palm against the other as hard as you can. Keep pushing for 5 seconds. Relax. Then push again for 5 seconds.
Do this ten times. Exhale as you push, and inhale as you relax.
Then press both palms in front of you while having their fingers pointing in different directions one set of fingers pointing to your left, the other set to your right. If your left fingers point to the right, your left hand should be under your right hand.
Push both palms against each other, the left palm pushing upwards, the right palm pushing downwards.
Exhale as you push, and inhale as you relax. Do this ten times. Then change the positions of your palms (left over right) and do the same procedures.
This exercises your forearms, arms, shoulders, and latissimus muscles (the muscles at the sides that give your body a V shape).

NECK PUSH
Gently move your head to your right side while your right hand gently pushes back against it. Do this once.
Gently move your head to your left side as your left hand gently pushes back against it. Do this once.
Gently move your head backwards as your left or right hand gently pushes back against it. Do this once.
Gently bow your head to the front as your right or left hand gently pushes against your forehead. Do this once.
This exercise strengthens your neck muscles. Never do neck rotations.

PUSH-UP
Do slow push-ups from 10 to 15 counts.
This exercises your arms, chest, shoulders, part of your abdomen, and part of your back muscles.

JOGGING
Jog in place for 3 minutes.
Then jog in place a lot faster for 2 minutes.
Then jog in place with a normal pace for another 3 minutes.
This exercise gives you a good leg and calf warm-up. This also serves as aerobics for your lungs and heart.

There! That ought to do it. After doing the above warm up exercises for some time, you should be ready start doing regular weight training and cardio workouts. Then just do 1 set of these exercises to properly warm up before you start each workout.