Exactly what PatrThom said. But just as tips for getting the line smoother in photoshop:
Make sure you have pen pressure turned on under brushes (F5).
You could also try using the pen tool and right click> stroke path to get those perfect lines. If you have it set to brush, and simulate pen pressure it should give you a nice smooth line no matter what. It will go from minimum brush diameter to maximum though, so in order to make sure the line actually goes the length of the path you create with the pen tool, adjust the minimum diameter under the brushes tab (Again, F5). You may also want to adjust size jitter a tad, if you wish to simulate a hand drawn line without going scratchy.
Learning hotkeys in photoshop is definitely important too. So much quicker. Off the top of my head, the ones I find most useful are:
[tab] will hide or bring up all your tabs
W= Quick select/ Magic Wand
T=Text
I=Eyedropper
S=Clone stamp
D=returns your foreground and background colours to default
G=Gradient
L=Lasso tool
X=swaps your foreground and background colours.
M=Marquee select tool
B= Brush
Holding shift while hitting the tool hotkeys will cycle through the different subsets. ie shift+B will cycle between the Brush, pencil and line tools
F will go full screen and back
R will allow you to rotate the canvas without actually affecting the file
[ and ] adjust the brush size. You can also hold alt, right click and drag left and right. Dragging up and down will change the brush from smooth to hard edge.
F5 brings up your brushes tab
F9 brings up your history/actions tab
Ctrl and - or Ctrl and + will zoom in and out
I also like shift+F5 (Fill)