This tutorial will show you how I make lineart in my current usual style. I will be drawing my made-up Creature, Honizu 2, in this tutorial. I hope it will help you!
First, make the sketch. Use the Pencil tool, size 1, opacity 74, smoothing 50%, freehand, on layer 1. Leave everything else as is. To make the sketch, the best thing to do is use basic shapes. Think of how each part of the character is shaped. Use whatever shapes you like-circles, squares, triangles, ovals, and whatever else you may need. Don't worry about perfection on the sketch. If you don't like how something looks on it, you will have 3 chances to fix it.
Now it's time to start the lineart. This is your first chance to fix what you don't like. Keep all the tools as they were in step 1, but increase the opacity to 100. Draw over your sketch and add the details to the character. Don't worry about perfection here, as this is not the final lineart.
Next is your second chance to fix what you don't like. Keep all the tools as they were in step 2, but increase the opacity to 137 and switch to drawing beziers. Go over your lineart. This still does not need to be perfect, as it also is not the final lineart.
Now it's time for the final lineart. This is your third and last chance to fix what you don't like. Increase the opacity fully (to 255) and switch to layer 2, but keep everything else the same. Go over the lineart again. This time you should try to make it the best you can, because this lineart is the final one.
Now click on the black circle on layer 1 in the layers menu, which I circled in red in this picture. This will make layer 1 invisible, allowing you to see what your lineart looks like without its sketch.
Almost done! Now it's time to use a lineart technique that will create a nice effect in your lineart. Use the Soft edge eraser tool on layer 2. Change the size to 10, increase the smoothing if you want to, and switch to freehand, but keep everything else the same. Now slightly, not completely, erase the ends of the lines that are not connected to other lines. This will help your lineart look even smoother and neater.
Now your lineart is done! Feel free to add any extra details you would like to add.
I hope this tutorial helped you out! ^-^