What do you need to become a stamp collector

I would say there are some basic rules which are applicable to any kind of collecting hobbies.
These are the basic rules that everybody should follow and abide.

Rule 1, you should have enough knowledge
To start anything without having the knowledge is very dangerous. The chances that you are making a mistake is very high. Regardless the kind of collection you are doing, you have to know what you are doing. This is the most common mistake of stamps collector. They start small by collecting used stamps. However, since the collected material really cost them nothing, they never bother to learn what is a good way of collecting the stamps. As the collection builds up, the value is also going up. These value is not always in term of financial term, but also in the effort used for collecting the stamps. Now, if you have spend so much time, then it is better if you learn something about what you are doing. Go and join the stamp-club and learn what is the proper way of collecting stamps. Collecting stamps is not just piling up used or new stamps, there are rules to be followed and unless you are following them, then your collection will be worthless.

Rule 2, you need to have the fund to spend
Money,...one of the most important ingredient of collecting. People like to collect things. Some people collect clothes, some people collect shoes and some people collect stamps. Whatever they are collecting, none of those things come free. There is a certain cost involved and you have to pay that with money.
So in order to have a good collection (whatever you are collecting), then you need to have the juice to run it. Without the proper juice, your collection will not worth much. Your collection is some sort of investment, except the investment is not in the form of money or stock, but in the form of stamps. The more you spend on your collection, the higher its value in the future, but you still have to spend in order to maintain it.

Rule 3, you need to have guts
Okay, now you have the knowledge and it just happened that you also have the money to spend as well. Ideally you should be able to build a good stamps collection. But there is still one more element that you need to have to make a good philatelist.
You need to have guts...or simply put, you need to have the courage to spend.
Not everybody has the gut to buy a piece of paper in the size of 2 X 2 cms at the price of $ 1,500 per piece. Even when you have the money, to spend $ 1,500 on a particular stamps is not an easy decision. The decision that you will spend your money on that piece of 2 X 2 cms may enhance your whole collection,.... but are you willing to do that.
By having the gut does not mean you should go on reckless buying spree, but with the combination of the knowledge, the buying power and the gut...... the result could be very different.

Well, of all the above rules, rule no 1 is the most difficult to obtain. There is no school that you can go to get the knowledge and the knowledge most of the time is obtained by learning from mistake. The mistake could be yours or somebody else. It is not always easy to learn something if you do not know what you need to know. So there is always a cost involves in the learning process, buying the wrong stuff, damaging the material, buying stuff in the wrong place, etc. All these are the cost that you have to pay, regardless how careful you are as a person.