I'm at the point where i'm happy where I am, so am perhaps not the best person to comment, but will take a risk.
I started in 2009 and set out to achieve a full round as soon as possible. I was 70% there by the start of Year 2 and would have been there within a couple of months of Year 3 except I broke my thumb and had to take 7 weeks off. I've been as full as I want to be since, but I stress I'm not the usual window cleaner - I've no rent or mortgage and no kids and have no desire to build an empire. Business-wise this is what I suggest any WC at least considers as it will in my opinion grow you business organically:
1. It's profit that matters, not revenue. You need to maximise profit however you can do it.
2. I raise prices every 2 years; a failure to do so will see your income eroded twice - once for your business expenses and then again when you spend whatever profit you make on day to day living. I raised prices on average 7.5% each time I've done it - last time this year. Next rise will be in 2015 all being well.
3. I price so I can take days off when its wet without worrying. See my post here:
http://www.cleanitup.co.uk/smf/index.php?topic=176256.msg1489911#msg14899114. I also price on the high side, but I am totally professional and don't let people down, do a great job, every time, am happy and smiley and - importantly for my business model - unusually flexible. See 5.
5. I am flexible with my custies, allowing what I think are reasonable reasons not to clean - builders coming, am going on holiday etc. "It's going to rain" is NOT a reasonable reason, but see 3. I also allow some of the customers I know are regular as clockwork in the summer to break for the winter. There's less hours for work and given my location I get a hell of a lot of heavy rain and snow. Winds where I live regularly gust at 80mph with rain to match, so having a few less custies to worry about in winter is fine - especially as I price them accordingly
6. I do a 5 year cash flow to analyse costs in advance - no surprises.
7. I never skimp on buying new equipment / spares - that way you are rarely down to equipment failures. However I don't buy equipment I don't need - whatever I buy has to earn its keep.
8. Get a good accountant.
9. Get good round management software and always aim to be as efficient as possible.
10. Do your books nightly.
11. Pursue all bad debts where it is efficient to do so - if you don't it has actually COST you money to do the clean that you are not getting paid for. Don't stress about it though (though I don't take my own advice here).
12. Analyse what the profitable elements of your business are and grow those. If it's domestic interiors - do em. Same if it's commercial work - target it and do it. You can only do this by analysing what you are doing.
13. Look at what people on here say, enjoy it and only believe a quarter of what you read. You'll soon see posts from the people who know what they are doing. When you do, ask their advice in a PM.
14. You can canvass any other windies' "patch", but only quote if the custie you approach is genuinely unhappy with the service they are getting - don't deliberately target someone else's work. Be friendly to all other windies you meet. You'll get more business by doing so.
15. Look and dress professionally.
16. Keep your vehicle clean, inside and out. Maintain your vehicle and your gear.
17. Say good morning to everyone who passes you.
18. Get your van professionally sign written.
19. Be prepared to work your so-called days off. Difficult if you are a family man though.
20. Decide what income you want and plan just what steps you need to take to get there. Mostly it's a case of canvassing, correct pricing and hard work.
There's probably more, but doing all this will, in my opinion, get you to where you want to be faster than anything else, and when you are full it's just a case or maintaining it, unless you want to franchise or employ which a whole different ball game I know little about.
Good luck.