Plugging away at a manuscript is very much like building a skyscraper.
You need first to devise a comprehensive plan if you ever hope the building to stand straight and beautiful upon completion. Hell, you need to plot out even how to get the materials to the top of the structure if you even hope to reach that phase of construction without it all crashing down on top of you, crushing your cute little yellow hard-hat.
Once the blueprints are in order, the skeleton - or outline - must be as firm as you can possibly make it. You need beams to guide the progress and a solid foundation on which to build your rock.
After that comes the most ardouous work of the whole project - laying one brick (or word) at a time. You need to use the best mortar you can find to hold the ideas together, leaving no holes for the harsh winds of criticism (the worst being your own) to blow through, weakening the structure from the inside out.
After the immense, long toil of building the walls, the last touches have to be put in place. The artful facades. The glimmering windows. The well-groomed shrubs inviting potential renters and businesses. This to me is the editing process, plugging in the beautiful while covering or removing the once-functional now-defunct parts that seemed so essential during building but now seem to hinder rather than improve.
Once the masterpiece of modern creative engineering is complete, what some call the most difficult phase of all begins - the showroom. The distribution of pamphlets drawing tenants to your building, if you can even find a company to support your best efforts.
Remember, even if your search for renters is long and hard, the building is complete. All you need now is to find the right clients to inhabit that which you've created - don't despair if it takes time - you've already done more than most could ever hope to accomplish.
Keep heart - even if you're the only one in the entire place, you get the penthouse suite - at least for the time being.