Guys, great news has arrived. The guide functionality in Blend first demoed by Unni Ravindranathan at the 2013 //build/ conference is now available for all xaml platforms in Blend with the release of Visual Studio 2013 RTM. If you haven't checked out Unni's session, make sure you do - It's really good and give a great insight into what's new for xaml in Visual Studio 2013 and Blend. You can find the session right here; http://channel9.msdn.com/Events/Build/2013/3-321 Dante Gagne wrote a nice blog post covering this topic as well, make sure you check it out.
This small tool guide tool included in Blend will help you achieving pixel perfect design and make the process much easier.
And hey - you can actually export the guides and use them on multiple pages - how cool is that!
Happy coding and thanks for reading, Deani