Jump-start Your Metabolism
The very best way to increase your metabolism is to become physically active. There is a wide berth in calories people burn during their daily activities, ranging from sedentary people, who may burn as few as 100 calories a day in activities, to very active people, like competition athletes, who can burn 1,000 extra calories a day. It was said that Olympic swimmer Michael Phelps was burning over 10,000 calories per day!
Physically active people burn more calories, even when at rest, because they have more muscle tissue. Muscle is "active" tissue, meaning it burns calories; fat is "inactive" tissue, because it burns almost no calories. So, the more muscle you carry on your body, and build through exercise, the more calories you will burn, even at rest.
Becoming more active will certainly begin the process of burning that furnace of yours at a higher temperature, but strength training specifically builds muscle tissue. Performing a variety of weight bearing exercise, and changing up your program regularly will begin to build that tissue, and help to rev up your metabolism. Be sure to work with precision, slow and controlled movement, and pain free range of motion. You will begin to see results in just a few weeks!
To build muscle, you need to tire them out, which will mean different weights and repetitions for different people. You can try starting with a 5 pound dumbbell, and start with a basic 3 sets of 12 reps of your exercise of choice, but fine tuning may be needed to actually find that tiring or fatiguing point.
Once a strength training routine becomes comfortable, you need to introduce different movements and/or add more weight. Weights should not be so light that they don't challenge your body to build muscle. If you can do 20 reps with your weights, then they are too light and you need to switch to heavier ones.