I often use visualisation techniques with my clients. This is one for when you've been stuck at your desk, or behind a computer screen; your energy’s low; you’re going into an important meeting or presentation. It might be good to do some physical exercise, to wake yourself up, but it’s not possible. So: imagine you’re watching yourself on a video:

You’re RUNNING UP AND DOWN STAIRS or SWIMMING LENGTHS OF THE POOL or HITTING A TENNIS or CRICKET or GOLF or FOOTBALL, or YOU’RE IN THE GYM… RIDING A HORSE… DANCING A TANGO… CLIMBING A MOUNTAIN…
First your breathing changes. Energy rises. CONTINUE for 2 or 3 minutes. Watch yourself, be there with yourself. Focus on something important – a key phrase – at the climactic moment of your visualisation, imagine yourself shouting out your phrase. You've really said it. Achieved something.
Doesn't that feel good?
You might want to try a second phrase… and a third. See yourself getting full recognition for saying it right.