Thanks! Hmmm I guess i just make sure the undercoat is as dry as it can be, so you can reposition as much as you want without risking messing things up, then i try to line my nails up so i can see if the lines are a sort of continuation of each other, if you get what I mean.

Also, for the cleanest lines I like to remove the tape immediately after I have painted over it, if you wait for it to dry or be mostly dry I've found the the nail polish on top will sort of tear leaving you with slightly less clean lines.