My approach was not specifically geared for the written. I am just proceeding as if I was preparing for the lab, that way I figured the written would come naturally. I have been studying on and off for a few years.
I have watched the following over the last year as part of general lab preparation taking notes along the way.
Written Bootcamp (Old and New Versions)
R&S Advanced Technologies Class New(Have watched multiple times)
R&S Advanced Technologies Class Old Versions
CCIE R&S Lab Preparation Bootcamp
Deep Dive - Multicast
Deep Dive - IPv6
Deep Dive - Security
640-863 DESIGN Exam Course (Certified CCDA)
642-611 MPLS Exam Course
642-642 QoS Exam Course (For BGP+MPLS Exam)
642-661 BGP Exam Course (For BGP+MPLS Exam)
642-813 SWITCH Exam Course (Recertified CCNP)
642-832 TSHOOT Exam Course (Recertified CCNP)
642-874 ARCH Exam Course (Certified CCDP)
642-902 ROUTE Exam Course (Recertified CCNP)
R&S Lab Workbook Volume I for CCIE v4.0 (Have been through thoroughly once, visiting sections randomly now)
R&S Lab Workbook Volume II for CCIE v4.0 (Only have done a couple of labs, looking to increase frequency in another month)
R&S Lab Workbook Volume III for CCIE v4.0 (Cycling through this repeatedly every couple of weeks to keep core technologies fresh)
Many books. To many to list for now. I would read some recommended books for the specific test I was gearing towards. Else reading usual CCIE R&S recommended books in the INE Videos.
CCIE R&S Written | CCNP | CCDP | CCNA Security | ITIL V3 Foundation | CompTIA Cloud Essentials