It had to happen sometime... you can't be writing up patterns and admiring lace and cable stitches and avoid charting forever!
Fortunately, others have forged this trail already.
At first, I just used ordinary graph paper to pencil in my plans, only to discover that the shaping - big surprise - looked very different once knit. So I was very pleased to find this free source of gauge-specific charting paper.
Also at first, I made a chart for myself and then wrote up the pattern as text.
But having fallen for stitch repeats greater than four stitches over four rows I can't really get away with that any more, so I was even more pleased to find the blog of a Very Clever and Very Generous person who figured out how to chart in Excel and related software and then went to the trouble to share the details.
And now you know what I'm doing today. Well, that and avoiding the resident box of Turtles.