Good morning, happy Thursday!
Let's exchange some wisdom today ^.^ 
Share a piece of advice, or a tip, from your preferred style of working. It could be something you wished you'd known when you started out, a nifty hack you've discovered yourself that others could benefit from - anything you think might be useful to people starting out in that field!
(PS-centric, I thiink CSP has cool features bypassing this issue)
@Curator When flatting (colouring in linework), to avoid spending ages using lasso/brush I tend to use fill (cmd/alt backspace for fg/bg colour) if my linework has enough closed lines. I think this is generally frowned upon because of the gap that can appear between line and colour. BUT selecting with wand/magic lasso then going to Select > Modify > Expand (or Contract) in the menu circumvents this. I've set these up as Actions.
@sajan This is generally frowned upon also because the *colours* have gaps between them underneath the lines, which can show up in print as duller lines or as white when the lines are slightly offset from the colour plates.
I use a script to expand+fill+deselect just like this that I use for doing big spot blacks in inks, but unfortunately it's not ideal for flatting. For that, selections that take nearby flats into account are needed.
@eishiya Huh! I didn't know that could show up in print (at least if the black is fully black) - thanks!
I probably shoulda noted this is just advice for people wanting to colour stuff quickly, rather than people doing any actual professional flatting work, and especially stuff that's going to be riso or screen printed
@sajan I think it depends on how you set up your plates. If you create them from a flattened version and use True Black, then it doesn't matter whether your colours meet under the lines, but then slight misalignments can result in more blurriness.
If you create your CMY plates from the colour layers and your K plate from your line and text layers (as is often done by pros), then this issue comes into play, but when the colours meet under the lines, misalignments are much less prominent.
@sajan If you just send your flat RGB or quickly converted CMYK files to a printer, then it doesn't much matter (but it probably won't be true black anyway, so your work will always look a little duller than it could).
If you're doing print prep in InDesign or Publisher though, e.g. to get some True Black, you might as well take extra care and generate K from your separate layers instead of a flat image.