being a mapper means taking almost 3rd quarter of your mapping time testplaying your maps over and over and over and over again. (I'm dead serious here). Doing testplays helps you a lot on getting the map flows smoothly so that you can get the gits of how fast/slow/smooth/jumpy your map can be as you map the song.
You need full understanding of the song that you choose to map so that you can get the idea on how you want to pattern your map based on your understanding. You may make some few jumpy or stream patterns but does it fit well with the song itself?
Also, don't afraid to ask the community for a testplay if they are willing to. Their opinions on your maps might be come in handy.
And important thing, every mod that you received for your map is very valuable and should take a look at it no matter what. You might be thinking "eww, this modder xxx doesnt like my pattern, that's why he/she want to nerf it", but these modders took their time to take a look at your mapsets, find some parts that are little bit off, and give some suggestion(s) to improve it. So, try to testplay that suggested part. If it's better than your previous pattern, apply the mod for that part. If it's not or you have a better way to create even better pattern than the suggested one, give some reasonable answer for declining that suggestion(s). This can help your mapping skills a lot.
One last thing, do not overmap.