I squeeze in a little extra ST/exercise by doing one set every time I use the restroom at work. One day is Squats, the next is Wall Push-up, etc. I pick one exercise and do a set of 15 every time. Gets in a bit of exercise without taking too much time out of work.
I will take things I need to deliver to people at work one at a time so I keep coming back to my desk. It helps me to walk more at work.
Getting started with exercise isn't as hard as we make it. We need to quit thinking about what we can and can't do. Stop thinking about when or where. Just get up and DO something. All your brain does is limit your body's potential.
When the day is wearing on me or I'm starting to feel down, I think of my dog and how would she handle this? It's either a wag of the tail, a wag of the tongue, or walk away. She's never down so why should I be!