Don't always "do"; just "be."
Parshas Beha'aloscha describes in great detail how, when the cloud lifted, the Jews would journey, and, when it came down, they would camp. It repeats this again and again. The Nesivos Shalom learns from this a lesson in avodas Hashem:
There are times in our lives, when the cloud is up - when there is light and things are clear and inspiring. We feel motivated and inspired to achieve and to grow. And then, there are times of darkness, when we are confused, uninspired, and stuck in a rut. We don't feel like doing anything!
The Slonimer Rebbe explains that the description of the clouds lifting and coming down shows us that when we are in those moments of light and clarity, that's when we should move! That's when we take on new things and push ourselves to achieve. But when the cloud is covering us, we stop. We camp. It's not the time to move, it's the time to maintain. We have to simply maintain what we have been doing, what we have been working on, and not worry that we are not moving and growing - because this is the avoda that Hashem wants from us at this time, and our work is to simply keep doing what we have been doing. We know that at some point, whether in 3 days or 50, Hashem will lift the cloud again, and we will be in a stage of light. Both times are a form of avodas Hashem, and the Torah is instructing us which avoda is needed at which times in our lives.
At Matan Torah - time of the greatest inspiration - Hashem came down in a cloud. He was showing that there will be times that this inspiration is not going ot be so strong but He wants us to remember that He is still with us, even in darkness, and this, too, is avodas Hashem. It's from Him! He places us where we are meant to be at every stage in our lives and directs us what to do within that. (נתיבות שלום )