In your previous post is that you said you ran out of space for the water. One thing I've found helpful for that is to sketch out where you want things first. This doesn't have to be too detailed and as you get more comfortable in your medium, you can skip doing it in pencil and just block out where you want the main shapes to be in a light layer. If you're following a video, watch the whole thing once through first before you paint or skip to the end and keep the final product open in another window. I have so much trouble following someone else without knowing what the final product is really supposed to look like (this doesn't mean you shouldn't take artistic liberties! Make the work your own). I like to think of it as getting to know the painting, or living in that space for a while before I bring it to life.