Disclaimer: This post is intended to be a wrap up of my experience to succeed in lab, this study methodology and all suggested here is based on my background and available times on week for studying, feel free to use it and adjust it to you own pace.
Being said that...
Get yourself use to read and read
Asumming that you have passed written and you feel like all the theory needed is covered I can assure you, that's not true. Even if you have passed the written you still need to read and re read technology and also be able to understand pros and cons of each design. A general rule that I can say is that to any desig you will need to be able to find the pros and the cons, if you can't you're just being shortsigthed and you're missing to cover all points in a given design. For this aspect is also key to get a group study, so let's talk about this one too.
Be in a group and collaborate as much as you can
Some guys claim that studying alone is the way that best suits them, that can be great if you're a giving a IE level exam or any written, but for DE is completely the opposite. I do really like to do this comparison and say that if you study alone you're just a vlan with a polarized HSRP gateway, despite of the nerd comparison what I do really mean is that you can't argue anyone! and that is not good at all, since I don't expect guys that argue for everything but I do expect people that say their point of view and discuss also why they have thought that caveat or pro in a proposed design. And remember discussions are a good thing, just like other good stuff don't abuse to them and use it carefully.
The methodology that we use in our group was to check one scenario every week, we set up call on weekend and on week we study by ourselves. You can use the scenarios in Orhan and Martin Duggan book, but since we run out of scenarios what we made is split ourselves in group of two and make modifications to create a specific scenario that cover some specific design concern, I do recommend you that in this "split" you choose to create scenarios based on your areas of expertise (in my case it was SP and DC :) )
My study methodology prior to lab was aprox 6hs per day (Monday-Friday), and 4hs sessions on Saturday. This by two months... and assuming that you have cleared written (i cleared mine long ago) and you have good design expertise (if not i will recommend you another 2 months of study), in my case I have near 13 years of expertise working on huge companies (like design scenarios hehe) and last 6 years on a Service Provider (who divest itself into two, nice scenario for CsC we made in real life!)
For lab strategy I can summarize my key points, some of them you will find it along a lot of posts, but this was really useful for me:
Color scheme for highlighting
I do really quick reading and that has a caveat, you can omit stuff, so be sure that you read all of the sentences and also take a color scheme to highlight information. I choose a real simple one: Green is good design option taken, Red is bad design or caveat on design, Yellow is constraint or requirement. I want to use pink for IGP info but i realize that info is so mixed that in second scenario I back to the roots and only use those three.
Be a chameleon
This is the mind status that you have to reach in the exam, you will have to be a chameleon to read all requirements and constraints and be ready to transform yourself in the designer of ABC Company to take the best choice, But inmmediately , in next scenario you will transform yourself into a Service provider architect being part of team who is evaluating X or Y technology. All this happens really fast and you have plenty of info around you to support you in this transformation, what you need is the ability to quickly focus in the job role that they have assigned to you, gather the info and take the best shot.
Suboptimal routing still works right?
I do really love to do comparisons of real life and technology and in this case I can think in suboptimal routing as a wrong (or not so good) branch in exam. If you have readed all Cisco Live material of DE you may be aware that in scenarios there is always several branches based on your selections, so even if you're not in the best branch you can get points (STOP! if you're not reading Cisco Live info for DE take a moment to review that, is key to understand exam flow). So in the time frame of an scenario the branch will become your life, so being able to manage bad decissions is important, because you will realize that you don't choose the best path (trust me, it happens) but they will provide you options to understand why you make that choice and you will have to choose the not so good and not so bad option to be able to continue, so don't get worried suboptimal routing still works :) and we know next time you will not face same mistake :)
Hope this help all the next aspirants, those new and those not so new. Also for those which have passed lab, congrats! and inputs are always welcome.
