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When building any pre-flop range chart, there are some main things to take into consideration. The most important of which are the following:
- value (rank of the card i.e. Ace)
these four things are the most important factors to consider in a starting hand, and they are the main driving force of pre-flop range charts (that is why the charts are filled in more towards the top left and empty at the bottom right and why more suited combos are included.
Position is very important as well (if not the most important factor) when creating pre-flop ranges. Opening ranges should widen up in later positions and include more hands that you would not play in other positions.
There are a lot of things that are considered when constructing these ranges. Like you mentioned, pot odds is one of them. Pot odds is not as important pre-flop because the equity of hands changes drastically when the flop is dealt but it is still something that should be taken into consideration. Implied odds is very important pre-flop because some hands have a much higher ability to become a strong made hand by the river than others. Blocker cards can also be a factor pre-flop, for example if you are considering a 3-bet on the button with A5s it can be a much more profitable 3-bet in the long run compared to 3-betting with other hands because it is less likely for your opponent to hold an ace.
You can also build ranges by using percentages and trial-and-error, although this works best if you have played a lot of hands and have a lot of data to go by. Hypothetically, you can say that you want to open with 30% of hands on the button and construct a range chart with the best ~50 hands. It is very important to use trial and error, if you find that you are getting into tough situations with some hands, consider playing them less often and playing them differently when you do decide to stick around.