Mark making using inks can be made with various tools and really helps to get away from precise work. Try cut coffee stirers, 'Cola' pens (see seperate blog), drawing ink pens with calligraphy styled nibs, feathers, cotton buds, old stiff brush, cocktail sticks.
You can also add resist before applying inks using candle wax edges and wax crayons. These help give a distressed and look when ink is applied over.
A range of 'inks' can be used; Acrylic FW ink (waterproof when dry), dyed drawing bleachable inks in black and burnt umber together with regular diluted household bleach, drawing ink (not waterprooof and thinner so more fluid), diluted acrylic paint.
Try mark making using a theme eg, circles, waves, leaves and lettering
Once dried, add highlights in white and metallic paints
Tear a range of different quality and colour papers and collage together. Then draw landscapes or still life using mark making
Create watercolour washes and then mark make over the top to create loose style artwork