Redraw your toadstool in pen. Rub out the pencil marks afterwards.
Colour in your toadstool. My toadstool is a fly agaric, a poisonous fungi with white scales on a bright red cap, often pictured in fairytail stories that fairies sit on.
Toadstools come in many shapes and colours and can form as clusters. My next set of drawings demonstrate other methods of such shapes, delicate colours and clustering.
The shaggy inkcap is drawn as a bell-shape attached to a stem. The brown rollrim has a dip in the centre of the cap and the gills are exposed. The dip is created with a circular mark and the stem is widened near the top for the gills. Use my stage by stage method I used for my fly agaric for the lilac bonnet, while the sulphur tuft is created with circles on top of more circles.
Colour in each drawing. Grey for the shaggy inkcap, yellow and brown layers for the rollrim, pink with brown highlights to the lilac bonnet (which I partially rubbed out with an eraser to lighten the colour) and yellow with orange centres for the sulphur tuft.
Redraw in pen and shade in if needed.
Finally colour them in. I used bright orange for the orange peel fungus, but lighter orange for the edging, bright yellow for the stagshorn, a light layer of yellow and orange for the birch polypore with grey, brown and green for the tree trunk, while the puffball is highlighted with yellow and grey.
Another fun way to ID fungi is to take off the cap of a toadstool and place it gill downwards onto a piece of paper. Leave it for several hours for the spores (seeds of a fungus) to drop. The result should be a print and as each toadstool have different coloured spores, the prints should also be in different colours.
I hope I have inspired you to go out and look for fungi for yourself, while drawing them in their many shapes, sizes, colours and textures. You will be a fun-guy if you do (sorry couldn't resist). The best thing about fungi is that you can find them anywhere. From the park to a woodland, all you need to do is visit the next day after a night of rain.