Here’s how I do my lineart/ base sketches for all my paintings.
NOTE: All the images listed here are WIPs at their earliest stages, so understand that this technique is just a quick foundation for the polishing work that will need to be done before your picture can truly be considered…

If you are a Photoshop user, Actions will make your life easier. If you’re anything like me, even saving the tiniest bit of time while working is a godsend.
This is the action I use to separate my lineart from the background it comes on after scanning it. (All that white.) I prefer my lineart to be on its own layer.
There are a few steps involved, but if you go through this you’ll never have to do it manually again. Under your Actions tab, hit the Record button. Then:
1. Go to Image > Mode, and switch to Grayscale. (Select Don’t Merge, Discard, if it asks you.)
2. Go to Select > Load Selection.
3. Go to Select > Inverse. (OR. Check ‘Inverse’ in the Load Selection prompt on the previous step.)
4. Make a new layer.
5. Hit Shift + F5 to paintbucket. It will fill your new layer with the lineart. Now you could stop here, but if you want to make this a super automated awesome process..
6. Hit CTRL + A to select the entire layer of lineart.
7. Hit CTRL + X to cut out the lineart.
8. Hit CTRL + Z + Alt to back up uh.. I think seven steps. You can see it indicated above. It should bring you back to the state of your piece before you did anything. Meaning, back to RGB if that’s what you scan it in with.
9. Hit CTRL + V to paste the lineart.
10. Stop the recording.
And you’re done! From now on, whenever you scan something in, you can simply hit that button and it does all the work for you. This might be common knowledge for all I know, but I thought it better to share!
WHERE HAS THIS BEEN ALL MY LIFE?
AAAAAAAAHHHHHHHHHH THIS WILL SAVE ME SO MUCH TIME

