If you draw a composition formulae like a golden mean or a triangle or a diagonal on a canvas then it will be easier to place the objects in the right place. Also the idea is to shrink things down a little rather than painting big. These will eradicate the problems that you are facing
@renoir thanks! If I may suggest, stick to one method. Mark's method is a teaching method, the paintings not necessarily have to be dark. You can employ the above method for a chiaroscuro painting as well. What I feel is that Sargent Zorn and some of the others also painted in the above shown method. So, paint the way you like and be the best in that. My basic brushes are the cheapest nastiest brushes that you can imagine. I use them exclusively because they provide abstraction and do not get ruined in the initial layers. I got softer brushes but need to buy more for upper layers of a painting though.
I think I have understood how these guys painted. It is significantly different from today's painting process which is more onto putting the values everywhere in patches and then make a judgement.
They sort of put several base colors (local color in mid value) on different areas according to shapes and then establish their lights and darks and created tonal variations later upon the local color. Effort is much lesser. Emphasis is on exact color. Brushwork was vigorous, blending upon the edges depending upon the focus of light. White highlights were put probably when the painting was dry. I will try to follow a similar approach on my next painting to see 'what is the difference?'
@Julianna sorry for such a late reply. I am not painting much these days and when painting - finding the wrong ways! Gouache is an opaque form of watercolor, so any art grade paper is appropriate. These days, manufacturers have invented a form of canvas for watercolor painting. So gouache is certainly appropriate for those only. Regular canvas is not suitable at all. Acrylic is a different medium from gouache. It tends to be more on the transparent side whereas gouache is more of an opaque matte medium. Acrylics are very versatile media but what bothers me is the drying time (not for my abstracts though, here it is a boon). But I like the readiness of gouache. Pick it up and paint...no fuss and it is very forgiving. Regarding color shifts...I guess all the mediums will change color during the drying process. For watermedia, this will definitely happen. watercolors, tempera and gouache will be matte. Acrylics will be darker.
@MoeyMichele I don't pre-mix much now. But for the 8-9 DMP paintings that I did in 2016, I premixed all the colors as Mark instructed. That sort of gave me a good eye for values. I still face problems due to lack of proper set-up and time. I put subjects in front of me and start painting by making comparison against previous value. For 10-15 paintings you must follow Mark's method fully and from time to time return to the method to regroup yourself.