What I do is just write an outline for the story's chapters so that each chapter connects clearly. This also helps to see where the plotline is going and where to throw the twists. Then after that, I lightly outline each of the chapters and the contents. Not too in-depth, but just enough so that once you start the writing, you know where to go. From there, you can flesh out the chapters as you write them and decide where to hide plot devices and twists. As you add them, make sure to append your outlines to remember where the devices/twists end up revealing themselves if you have a lot of them.
Too much outlining I've found is detrimental to the writing process, because writing the exact same thing twice kills motivation.
If clarity is an issue, grab a friend and force them to read your writing. Simple feedback such as "This is too vague" or "I don't understand" can be crucial, because as the author, everything makes sense to you. If someone pinpoints something and helps explain why they're confused, you start to learn how to avoid making things too contrived. There is a difference between contrived and veiled, the dividing line is thin though. Takes a bit of practice to grasp that.
As for editing, you are your best editor. You know where your mistakes are and how to fix them in the best way that compliments your writing. Just don't edit directly after you finish writing. In my opinion, I've found that you lose motivation because reading the same thing twice is tedious. Give your eyes a break, come back to it after a couple hours, watch a movie, play a video game. As you edit more, you get better at spotting your errors and sometimes catch your errors as you write them.
As for resources, word pad for outlining/drafting and either MSWord, OpenOffice or Jarte are excellent tools for the actual writing process. I personally use Windows Live Writer, because it allows me to publish directly to my site once I finish writing. Also, assign yourself a schedule and set goals. Being aimless is never good if you're aspiring to get something done.
Hope that helps for the most part. A lot of the writing process is learning what helps yourself, so some of this may or may not work for you. :3 Have fun.