I feel sorry for you really, changing over to wfp was the worst time of my life.
I got really depressed going to work, also was embarrassed, dont ask me why but i did.
I used to cringe everytime I pulled the hose up the customers path, In the end i just couldnt face going to work.
It took 18 months until i was over it, now I dont give 2 hoots I just get on with it and have never looked back since.
I must also say In the 3 years or so since i went wfp, I have trebled my turnover, dont know how much of that is down to wfp or my business accumin ?
The answer to your question, I would say there isnt too much you can do really pre wfp, as everything needs a clean or 2 before they come perfect anyway.
Practice on your house windows and get a full understaning of what is actually happenning with the dirt on the windows, maybe go on a wfp course, and go out for a couple of days with an experienced wfp guy.
Dave