How to get a faster metabolism?

Exercise. Exercise not only burns calories, it also raises your resting metabolic rate after you finish exercising.
↑ MuscleMass; Verify. Good thyroid function & move a lot. Maintaining muscle cells is much more metabolically demanding than fat energy storage cells, thus ↑ muscle cell mass, make sure TSH is lower normal (inverse relationship to thyroid function) & move a lot, minimize sitting.
Speed metabolism. Weight training builds lean muscle which is metabolically active around the clock, day and night. While some studies suggest that cardiovascular exercise may stimulate the metabolism for as much as 48 hours after the exercise, it may be much less time. Both are best in combination. As well, eating a small healthy meal of lean protein and complex carbs every 2-3 hours speeds the metabolism.