It’s very important in a games to watch how your opponents play in each pot. Even when you fold, you should still stay focused on the game to better understand how your opponents play. 
This will allow you to see what moves other players make when they have the best hand, and what moves they make when they don’t have the best hand.
There are two main reasons why you shouldn’t spend too much money on the table as a beginner:
The first reason is that players at higher limits will be stronger than players at lower limits. You will have less chance to beat your opponents and you will waste a lot of money trying to learn poker in the process.
The second reason is that you only want to enter pots at the limits you can afford to play. You should not play at limits where you are going to spend money that you can’t afford to lose.
You will regularly find yourself holding half a hand that needs just one card to make a flush or a straight.
The most common beginner mistake is overestimating the value of suited cards. Flushes are not as frequent as you might believe, and if you try to compete with two small suited cards, you will probably lose all your money to a higher flush if it comes.
If you’re playing online or in a casino, watch the alcohol consumption. You might be more relaxed after one or two drinks, but it might also lead you to playing very bad and getting easily distracted.