Anywhere you see a tag on the website, hover over it for more information! Handy dandy!
Also, we've added a ton of tags for common flaws like ad hominem arguments and false dichotomies! Dandy handy!
Shoot us any ideas you have for what information you'd like to see in these tooltips. I PROMISE THE DEVS WILL IMMEDIATELY IMPLEMENT EVERY SINGLE SUGGESTION.
(Definitions are only available for LR tags currently, but RC definitions are coming soon :P)

I'm a big fan of the Economist in general and as an LSAT study tool. You're on the right track in terms of process, as well.
I'd recommend making low-res summaries / structural maps of the articles you read. Their arguments tend to be structurally complex but also very clearly expressed, so it's good practice for building large mental (and written!) models for long-form arguments.