Some people aren't that way. Perhaps the weekend was rough. Perhaps it takes so caffeine to get some people going that it doesn't kick in until Tuesday. I get it. One of the biggest things I've found in making Monday successful is:
Don't lose momentum over the weekend!
Sure, everyone needs a break, but if you touch on your project (book or otherwise) over the weekend... even if it's some sort of periphery project like tweaking an outline or doing some research. Something you put off during the week that you can do during a lull in family time or while your significant other watches television will give you a sense of accomplishment and will keep your head in the project.
I'm nearing the end of my work-in-progress, always an exciting, yet bittersweet phase in writing. I find it crucial to keep my head in my story over the weekend toward the end of a manuscript. There is so much on the horizon that it's easy to turn two weeks of work into four. Editing looms. The next story idea, shiny and new, beckons like a seductive lover. Now is *not* the time to lose focus and end up with a sloppy ending.
So I soldier on. Ready to finish strong and move on to the next phase in writing. Carpe Monday and dive in!