After you set your monthly goals, you can break those down into weekly goals. I have never done this but am considering it for 2011. I think it will help keep me on track better when life throws me a curve or I just feel tired or unmotivated.
If you've set four monthly goals, perhaps you want to concentrate one week for each goal set. Or maybe you want to work on the most important (to you) goal. Or if one of your goals is easier, like polish and submit a manuscript, that might be the one you work on the first week to get it finished and have that sense of accomplishment. Remember not all of your monthly goals have to be "hard". It's nice to have an easy one that you can get out of the way so you can check one goal off and move on to the next.
This is where your own unique preference comes in because what works for me might not work for you. Believe me I am more motivated when I can check a goal off within the first week of the month as being complete no matter how easy it is. But maybe for you, it's better to complete the harder task then reward yourself with the easier one at the end of the month.
Either way you will get to the end result, completeing a monthly and making forward movement in your writing career.