Momentum is when things start to roll a little faster. When deals are easier to sell, or investors are a bit more excited about what you do. Things feel easier.
When you start to have momentum, the time is to accelerate. Like when surfing and see you a wave, you keep riding and riding because you know momentum will stop at some point. So you leverage the time you have now when the opportunity presents itself.
After a certain time know that momentum will stop. It's good to have this end goal in mind so when it does happen it's not a surprise. Or when the slowness starts happening it's best to visibly state the end goal to have momentum until the very end.
At this point the next step is to find another momentum wave. It may be a short or long break, but no matter your job is to lie low until that wave starts again.