Hi Janne, I am a beginner and have the same challenges. I finally figured out that for now I need to use the same rough or cold pressed 100% cotton paper every time because the finish of the paper differs from brand to brand and also the absorbency. Also I need to use the same few paint pigments and same size paper and same size brush(es) for that size paper until I manage to get the feel of how to use my materials/ tools. I practice the strokes I am going to use with the paint mixes I made up, focusing on tea/milk/cream/sticky(aka 'neat' staight from the tube) consistency before I paint a painting.

I have been using my hair dryer to dry in between my planned wash stages, (realizing this changes the painting), but as an experiment I dry for 30 seconds then paint to see what happens, then 30 more seconds, repeat...etc. I will do this until I get the feel of how I can make the painting come together. This helps me to get the hang of just what does my paper looks like when its ready for certain brush strokes and paint thicknesses for each wash or step.

Someday I presume I won't need the hair dryer and will know from experience and all becomes second nature, but for now, I am painting alot and repainting the same landscapes as experiments, just to learn what will most likely happen. Hope this makes sense.