Resolve to give each of your clients at least five minutes every month (off the clock) to check in and see what they are up to.  For more, check out this post talking about Rosa Say’s “Daily Five Minutes.” 

Here is last year’s resolution:

Review the look of your normal invoice.  Then ask a seven year old to do the same.  Are they readable and easy to understand?  Do they have all of the information your client wants or needs?  It also wouldn't hurt to call a few of your best clients (or the people in charge of paying those clients' bills) and ask them if there is anything you can do to make your bills easier to read and understand.