If you simply can't think of an background or you are too lazy to do an very detailed background, this tutorial is right for you ! Now i will teach you how to make an very effective simple background for your drawings !
Begin making your BG by making an simple gradient with two colours of your choice. Since i wanted my drawing to be very light and to have an warm effect, i used yellow and pink.
Simply to do this, just apply both colours and blend between the colours with the watercolour tool.
Then make a new layer, pick an darker colour and start dapping random dots all over the canvas. Try to make the balls big and very bubblish, so it looks floaty/dreamy.
Make sure to make the bubbles in low opacity and if you have a tablet, the pressure will do it.
Then pick the airbrush-eraser and pick just a smaller size of the ball and make a ''hole'' in the ball, so the center becomes perfectly transparent and it will look like an bubble.
Moving to the right picture, pick the normal pentool and set the brush settings so that Opacity, Colour and Spacing are at 100% and start making straight lines from top to bottom and bottom to top. It should look like the picture in the right.
Again, pick the airbrush-eraser or soft eraser and start softly erase the ends on the straight lines you just made, to make it look faded.
Then the last thing is to add frames ! Do it as you please ^^
I know the BG itself looks very abstracty, so here is one of my drawings where i used similar technique~
I hope you enjoyed my little tutorial and don't be afraid to give some feedback ^^
Thank you for viewing !