The first thing you have to do in order to differentiate is go full on into a digital project based and paperless environment. You have to come up with assignments that can be done completely without paper, but you can still give students the option of turning somethings in on paper. Also, this does not mean things like essays are gone, and while I am not a worksheet person, you could even still keep them with a quick transfer into Google Drive.
In my classroom, we have started a Historical Newsroom theme to our class. Students have some projects that everyone has to do, but they also have projects that are differentiated. Some of the projects everyone has to do include discussion questions on Edmodo, Analysis of Youtube Videos as Sources on Google Docs, and Quizzes on Edmodo. Where the differentiation really comes in is what project categories they are assigned to do in a unit. We have five Notebook, Parody Projects, Social Media Projects, Writing, and News Broadcast. They are also in order from what I think are the easiest to the hardest. I differentiate for students by what project category I assign them to do, and I usually assign 2-3 of these type of assignments per unit. For instance the lowest performing students might get the Notebook and Parody project as Assignments while the highest may get the Writing and News Broadcast. These are also differentiated by giving students a choice between 4-5 different projects to do. In the Parody category for example, they can act out historical figures, do historical caricatures, do a fake interview of a historical figure, or do a fake radio broadcast.
The thing about differentiation is you have to have a way to organize, and ed tech makes it super easy. It's very hard (especially in higher grades) to run off multiple activities and do center based instruction. Technology allows you to give students different checklist and workflows for a unit based on their ability. I have used two strategies effectively: Differentiated unit Checklist on Wikispaces and Unit Work Flows on Symbaloo
To do the differentiated checklist you need a Wiki. I love using Wikispaces. You create a wiki for your class. Wikispaces will allow you to do multiple wikis. You create pages on the wiki for each student. On each page you put a checklist of their assignments that are differentiated by group. This sounds hard and to be a lot of work, but its not. All you have to do is create 4 or 5 different tables for the different levels in a word processor. You can then cut and paste based on the level you think each kid is on. You could even adjust the checklist in special cases for a kid who you are trying to reach with a special assignment.
The other way (and my current way) I differentiate is by using Symbaloo. I first write up all my assignment directions in Google Drive. This allows it to embedded in Symbaloo. I then create four different level workflows. Basically, it is just tiles of the Google directions in the order I want the student to complete them for the unit. Each of those workflows is differentiated based on the project categories I ask them to pick assignments from as explained above. When they are to pick from those categories, there is an icon that tells them to go to the Webmix with those categories. If you want to see an example of this, http://www.lockhartushistory.com/birth-of-a-nation1.html.
While I have share with you my ways, there are SOOO Many other ways out there to differentiate. We can't really expect teachers to print off and go to each student and assign individualized work. Tech allows you to give them choices and assign categories for them to complete assignments out of based on their level.