I suggest you keep your money in your pocket and don't pay anyone or buy any domain courses.
there are a lot of folks who will take your money, just because you have some to spend.
figure out what you want to invest in, whether it be 4 letter.com, 3 letter org, brandables, one and two word .com, phrases, etc.
then have a budget in mind, for such acquisitions.
don't be in a rush, because domaining is not going anywhere any time soon.
read thru the domains wanted section and go back at least 7 years to see what buyers have been looking for and how much they were willing to spend
read thru the sales threads and see what sellers are asking for the domains they post.
notice what gets sold and what doesn't
just keep reading and ask the right questions.