Use a flashlight hello at a steep angle against the wall to highlight your mud and texture work BEFORE you paint it. The flashlight will show you everything you did that still needs work. DIY drywall is often done after work, at night. Once done, and you open up the windows and that natural light comes pouring in from any adjacent windows and it looks terrible. That's why you check with a flashlight first. Any seam you are mudding should be feathered out at least 6" on either side, and honestly probably even further if you're new, to avoid looking like you have worms all over the wall.