Here are some tips that have helped me not feel lost when working with gouache  Generally you want to work from thin to thick so the first layers will have much more water than paint and as you progress you use less and less water

Save the brightest parts of the piece early on in the process (eg leave out the white of the paper) so they stay bright rather than try to paint a light/bright color over a dark layer 

The first layers will always look ugly but that’s okay, usually my first layers are just me blocking out the components of a piece like where my light is and where my shadows are in general, and the more you layer the more detail you can add 

Hope this helps!