Its great that there are many successful domainers that blog. It gives those new to the business some insight into what domaining is like. It provides some strategy and some interesting stories from the early days of domaining.
But only you know you, and you should take your cue from yourself. Its fine to read what certain domainers are buying, but that may not make sense for your budget or your intellect. You should focus on what you know and like. What do you have passion about ? Because that gives you the most options for making money on a domain.
If you love baseball, then regging or buying a good baseball domain makes sense. Maybe you cannot sell it right away, but you can use the domain for a blog, where you can share your thoughts daily. You will not find it a chore to write because you love the topic, are passionate about it, and you genuinely have something to say about it. Maybe you start an ecommerce site, selling baseball hats or another related product.
On the flip side you may have purchased a domain about a topic you know nothing about. So right from the get go you may not have even paid a good price. Since you don't know the topic the name might not be good. While you are waiting to sell the name it will just sit there. You will have no motivation to build a site, you most likely will have nothing insightful to say on the topic.
You may also follow the big guys into some speculative type extensions. The only problem there is they have a much bigger bankroll. So first off they will get the better, more valuable names, as they can certainly outbid you in an auction. Secondly they can afford to be wrong a lot more than you can.
There are many ways to make money off a domain name, make sure you start out taking your cue from who you are and what you know. Then learn how to tweak from those who have succeeded in domaining.