Good critique partners and beta readers are worth their weight in gold.
My readers are an integral part of my revision process, and when we're talking about getting a book into a polished state in as quick of time as possible, one of the first things to look at is finding the right readers for your books. And then KEEPING those right readers, once you've found them.
Finding appropriate, helpful readers, quite honestly, is a matter of trial and error. Your readers, hopefully, should enjoy the majority of what you write, even if they do see flaws in it. You don't want the process to be like pulling teeth for them, or it will take them six months or more to provide you with feedback.
Part of finding good readers is BEING a good reader. When someone asks you for help with their manuscript, make an effort to clear your schedule and read it in a timely manner. Then, hopefully, they will do the same for you when it comes time for them to read one of your books. Try to provide the most helpful and fully-explained feedback you can. Think of how clearly you would want it worded if you were hearing it about your work.
Then, when it comes time to sending your work out to these helpful, timely readers, don't send them unpolished garbage writing. Make it as good as you can on your own before sending it out. Get yourself a text-to-speech program (I use the one on my Kindle) to play back your story with an ear for typos and clunky sentences. You can hear the difference between "She went to her house" and "She went to her hose" even on the most computerized voice. Honestly, I think it comes across as disrespectful to a reader's time if you haven't taken the time to make your writing as easy as possible for them to read.
When it's as good as you can make it, then send your writing out to one or two people (save some readers for the next revision round - always assume there will be a next round).
There are some parts of the process that are going to take time, they just are. But the idea here is to make them take the least amount of time possible.