This is a huge question that no one can answer in one simple line.
It depends on what cards you have, your position at the table, the street that you are on, the size of the blinds, the size of your stack, the size of the pot, the number of opponents still in the hand and their position relative to you, the action to you, the tendencies of your opponent(s), are you on tournament pay bubble. probably a couple more things that I can’t think of right now.
It sounds like you need to learn some ranges. Ranges are what hands you are willing to play in certain situations.
The best one to start with and to build upon later is your pre-flop range. That is, which hands are you generally willing to pay to see a flop with, and of course this goes with how much you are willing to pay.
A standard pre-flop range is usually about 30% of all hands.
I will explain this. 100% of all hands means literally any two cards (we are talking about hold’em with a 2 card pocket, as opposed to Omaha with a 4 card pocket - I will ONLY talk about hold’em because it is what I know). So someone who plays 100% of range will play AA (the best hand) just the same as 72o (the worst hand) and anything in between.
So to play about 30% of all hands means to play only AA down to about J9o or T8 or thereabouts. Someone more knowledgeable please correct me. This means that if we get 64o or 83s or other ‘garbage’ we fold. When we get QJo or KTs, we can bet (or maybe call a bet) to see the flop.
Someone who plays say 50% of all hands is considered ‘loose’ and someone who plays 25% or 20% of hands is considered ‘tight’. If we play against the same player for 50 hands and we notice that he sees the flop 35 times or more, this means that he is playing very loose because it is nearly impossible to be dealt cards in the top 30% of range 70% of the time. So if we play tight at say 25% range, when we see the flop against him we usually have a better hand. ; ) This is called range advantage. However, if we are too tight, we just won’t play enough hands to make any money, and when we do, opponents will know that we have something good and they won’t pay us. : ( That is why we want a balanced range not too tight and not too loose.
In my experience, I would recommend that a new player start a bit tighter and only play 25% of range. Better cards are just easier to play with, easier to read the flop with and know when you are ahead. Then as you gain experience and skills, you can ‘widen’ your range - get a little looser, gradually.
Also, against bad players, it is usually more effective to play on the tight side, as bad players tend to play too loose and you can easily have that strong range advantage against them.
But before you try this, though, you need to know about position. Here are the positions at the 9-seat table:
SB BB UtG UtG+1 +2 LJ HJ CO BT
Small blind (SB), big blind (BB) and under the gun (UtG) are considered early positions. +1, +2, lowjack (LJ) and ususlly hi-jack (HJ) are considered middle positions (or MP), and CutOff and BuTton are considered late positions.
And these are the seat at the 6-max table.
SB BB UtG HJ CO BT
SB and BB early, UtG and HJ middle, and CO and BT late.
the late positions (CO and BT) are the BE$T positions $$$$$. There is a big advantage playing in these seats because we get to see everyone else’s actions before we decide to check bet raise or fold. ; ) The early positions are the worst, and the middle positions are the middle but more similar to the early than the late.
What this means that we will play TIGHTER in early and mid positions to make up for the disadvantage of acting first, but looser in late positions because our decisions get much easier going last. So if we play 30% of all hands, we might play only 15% from early, 20% from middle and maybe even 35 or 40% from late. ; )
But this is all very very basic and there are many details that might make you alter your range and make you decide to fold a hand that you would otherwise play, and this would make a very long response.
I would love for someone with more experience to refine or clarify anything that I’ve said, yet hopefully keep it rookie simple for now.