Unlike most of the content on this blog, this one is for the beginners. A charitable MechWarrior named Pirlantota has come up with an excellent website made for the beginners. It touches upon pretty much everything to get you going if you're new to MWO. Not only he has written guides to cover pretty much everything in MWO, he also made lists of other helpful guides and streams as well. The website looks a bit dated, but the content is solid.
If you have finally convinced a friend to check out MWO and want him to get a headstart, this guide is just perfect.