Everyone has their creative energy highs and lows. For me, the mornings are the best time for ideas and for creating. My energy level is high in general and things seem a lot more clear. Once I have that first cup of coffee, I am ready for my mind to open.
I do feel like I waste this energy all too often on trivial things that could be accomplished with less creative energy. I also find that if I don't do something to release this energy, I become agitated and irritated and will end up feeling tired.
I do think that the act of making art and being creative releases important chemicals into my brain. During a painting session I feel lucid, calm and happy. After a long session, I am tired, but feel like I accomplished something and am content. Knowing that I have a project in progress can also make me feel good.
My least creative time is in the evening. I can get some grunt work done like stretching a canvas, adding one block of color, building a frame but it is not a good time for creative thought.
I do get that burst of thought that keeps me awake in the middle of the night. My dreams can give me ideas for different things.
I like to listen to other peoples ideas. Reviewing student work, architectural or other artistic things, can really stimulate my creative side.
If I had to give advice to anyone attempting to draw, paint or design it would be to figure out your creative energy schedule. I would also tell them that if they are stuck on something, to get away from it and come back after they have done something completely different.