I do beginner domainer coaching... here are a few tips on getting into the game:
1. Buy Correctly
Remember, you never make money when you sell something. You always make money when you buy it correctly. Read those sentences again. They are critical. There is no money to be made on a domain that is not valuable, or that you've paid too high a price for. This leads us to the next point...
2. Get Educated
In many ways, your self-education is a far more valuable an asset than your domain portfolio. And this goes for most pro domainers. What they hold in their minds is worth far more than what they hold in their registrars. For you can always lose a business or empire, but with what is in your mind... you can get it back. Given the choice of one or the other... the wise will go with education every time!
3. Specialize
There are well over 20 categories of domain... here are just a few of the more popular ones:
EASIER
Liquid Domains (LLL, LLLL, etc.)
Brandable Domain
Discoverable Domain
Dictionary Domain
Exact Match Domain (EMD)
HARDER
Geographical Exact Match Domain (gEMD)
Adult Domains
County Code (ccTLD)
Domain Hacks
Emoji, Pinyin, & IDN Domains
First Names & Last Names
Geodomain (Country, State, City, Suburb, etc.)
New Generic (New gTLD)
Numeric Domains
Partial Match Domain (PMD)
Phrase Domains
Seasonal Domains
Ultra-Short Domains
True Premium
I've separated them into in what is "in my opinion" the easy ones for a beginner to start understanding and profiting on, and the other types which to me seem more specialist and with less clear or harder to learn "rules". Which brings us to the next part.
4. Rules
Each category has it's own floor prices and evaluation rules to determine the optimal buy and sell prices. You will need to immerse yourself in the chosen category and get familiar with all of the jargon and peculiarities around that specific category.
For example with Exact Match domains many find the Rosener formula helpful in determining potential value:
For .com domains: Search Volume X Cost Per Click X 12 X 0.33
For .net & .org domains: Search Volume X Cost Per Click X 12 X 0.33 / 10
Remember that the formula doesn't give you the domain sales price, but an indication of potential value, especially when comparing multiple domains.
Another example of a category would be the Liquid Domains category where for example you would learn about various configurations of 4 letter .coms and how the ones without AEIOUV are known as Chinese Premiums or Chips and are far more valuable than their counterparts... which are also valuable, just for being 4 letter .coms. And how the pronouncable ones are Western Premiums... and even the remainder have decent floor prices. And then you dive deeper and learn that certain letter combinations are more in demand both in patterns, and in which letters are used specifically.
And then there the "brandables", which seem to be gaining strength as there are more start-ups and trending niches than ever before, and more and more sites catering to them. Which takes us to the final point.
5. Marketing
You should never buy a domain unless you have a clear idea of who you are marketing it to, and how you are getting in front of them.
Some people are targeting very specific niches and reach out to them by cold calling companies they see ranking in Google or spending on Ad spend. Others are using various tools to email massive lists of companies that are either in the same niche, or have a related domain name.
Others use facebook groups, linkedin groups, skype groups, and online forums like this one to network and promote their domains.
Others list their domains for sale on auction sites like Sedo, Godaddy, Flippa, Ebay, and many others.
There are also many marketplaces best suited to each category, for example for brandables many would try and get exposure by listing on BrandBucket, BrandRoot, BrandPa, or Namerific for example.
Personally I think the number one neglected thing people should be doing but aren't is having a decent landing page on each domain... a large percent of sales come from people just typing in your domain to see if it is available.
I also personally list my domain on over 100 marketplaces because in this world exposure is a large part of the battle.
6. Bonus Point
The strongest tip I can give besides deeply familiarising yourself with the industry by reading all the blogs, and studying Namebio, etc. would be to try and find a mentor or coach. Obviously if you have a friend who makes good bank doing domaining... try and pick up as much as you can from them.
Make friends with as many people in the industry as you can, and they don't have to be in the top 10 domainers worldwide... just doing better than you... then you can learn from them.
Feel free to reach out to myself or anyone on the forum that sounds like they know a little more than you do, and ask questions... most of us are just happy to pass on some good advice.
Don't be put off when I said I do beginner domainer coaching... I'm happy to give free advice. The coaching is really for people who need that something extra, and not just a few pointers in the right direction.
Stick with it, don't be discouraged... when you make your first 1,000+% profit it will all be worth it.