Inside my head. Usually it turns out alright.
I'm currently working on something where I was going with pinwheels but those didn't feel right so I wanted to lay the squares with the design fabric down and the plain fabric up. Still not floating my boat but I think I found a solution. One day I'd like to go the graph paper route but right now I can't. I have a toddler who wouldn't hesitate to sniff colored pencils out and redecorate. She gets stealthy so it's easier to not have them then try to hide them. I swear one say she will be CIA lol.
Till then I just wing it and go from there.