Have you got a uniform, van - signwritten, is your business as professional as it can be, Does it stand out from the other window cleaners in your area.
You cannot force the situation (I tried to do this for the first three years and just got frustrated with the lack of development).
If you keep offering a high quality service that people will recognise when they see your van, you and your uniform, get leaflets out there, the law of averages is that you have to gain customers and therefore develop a larger client base.
I personally would not go down the commercial route again. Time with the people you love is irreplaceable and a large residential round will give you all of the money you will ever need, financial freedom and a great deal of personal satisfaction and you will be at home every night.
I am building a residential round again - up to 60 plus customers, not putting anything into it but every month I go out I am getting more and more cleans.
Good luck - whatever you achieve never take it for granted or take your finger off the pulse!!!
Rob