The abstract pictures have often got inspiration from the exiting lines and surfaces, you might find in the nature, in stones and rocks.
But often a picture will be created, when you are working with lines and colours on a canvas.
Suddenly something solid will appear on the canvas, and you can then work further for creation of a picture.
But the nature is the biggest artist, as we all know, and this might give you several possibilities for inspiration.
I have several years worked with sketches painted using crayon and water colours , and these sketches have as mentioned later often been used as model for bigger pictures.
It is interesting, that our twin grand children can also without any problems give inspiration for new collective abstract works, when working together with them.