1. one or two years of domaining is nothing. it's mostly educating time, one way or the other.
2. most success stories and meteoric rises of the last 4 years were made in a full bull market that has crossed many businesses. this means when the tide turns we will see many people naked, and many certainties about the market be turned upside down.
3. domaining is like every other business. it needs time, research, planning, hard work, discipline and making mistakes. luck is very important also. forget the easy money stories. they are just lures and outliers.
4. you need to learn what sells, what can be worth in the future and what can be just hype.
4.a. for that matter, you need to learn how to ride an idiotic trend that is made up by collective delusion, but be aware that you are playing a game and it will end. that is, you should know that it has no long term future but be willing to join the masses and take part of the money on the table while it lasts.
4.b. most of your money should be spent on good domains, that you will be able to identify after point 3. I can give you an example of good segment: short domains. But really short, not the nonsense of 5 letters or more or 5,6 and more digits domains. stick to 2 characters and 3 letters on .com. This is sound investment because human behavior will always be attracted to uniqueness and scarcity, specially when a bull and optimistic market sets up. you need "just" to be careful and understand that everything will go out of fashion in a bear market and money doesn't grow out of trees. So you should not being paying high values even on good and solid domains *today*.
5. most of this business is building a good portfolio and waiting, for several years. flipping is not for everyone, and should be done only as a side tactic to make some money to fund better inventory or pay some bills. most of the flipping opportunities result from point 4.a.
6. trim your portfolio. playing the high numbers game is just for a few. you need to really know what you are doing, have a very good and streamlined process with well controlled expenses. Most of the people that succeeds in this model where people that have been around since "the early days" where they could build big portfolios with good available domains or with a good global average value. the few others where "just" really smart or had some good monetary backing to start it.
7. understand that the buying part is the most important one. it is better to buy low than to buy high, and it is better to buy one good domain than several mediocre domains for the same total amount. this is very obvious and looks like a stupid thing to say but the fact is most are not aware of how important this is and how this is tied to the success of most investment decisions you make. you cannot buy a 2 letter .com domain today for $1k. but you should not also pay $500k today for one. the deal is to buy at a value where you can have some margin to coupe with market fluctuations. how do you do that? by being around in the business for some time, by point 3, and developing a good insight into what is a good value proposition given the current status of the market and the foreseeable future (for what it can be humanly grasped).
finally, giving up is not the solution in anything. at least not before revising what went wrong and what can be done better and then try again.