We all hate drilling down through directories searching for our files. I wrestle with this all the time with Windows - I wish the feature I'm about to define existed there!
The File Open dialog box has a column on the left that is customizable. It's super easy to place your frequently visited directories in this column for super fast access. All you need to do is drag a project folder onto the column and windows will create a shortcut to it. You can delete the current directories listed if you don't like them! The below figure shows you the shortcut menu that pops up when you right click in the far left column.
You can drag and drop directories over to the column if that's easier for you. I have all my current projects that I am working with as shortcuts so it's easy to find my files when I need it. I never have to waste time wading through directories! (Like I said - I wish Windows Explorer had this cool feature - and "no" Favorites doesn't cut it for me).