There are a lot of real factors to the occupation of being a crypto miner. It is not merely plugging in a miner and connecting it to any pool. It does not matter if you are using GPU, ASIC, or CPU there are some real factors you must consider.
We will cover the main factors one should think about when choosing a mining pool, also if the factors are not in your favor you may wish to create your own node and make a private mining pool connected to the specific coin you want.
Latency should be the number one factor you should consider when choosing a mining pool. This is the time and distance it will take for the communication from miner to server. The further the distance the less coins earned due to latency.
Each mining pool has certain pool policies that may or may not adhere to the consensus of the blockchain. If the pool is not in consensus with the blockchain you may be cheating yourself as well as cheating the system. Also there is strong possibilities that the actual mining may be continue to be rejected by the consensus.
Another major factor in choosing a mining pool, would be the actual fee that the mining pool charges for you to mine on. If the fee is too high, it will also be cutting into your earnings.
This should be the rule of thumb when you choose a mining pool. If for any reason the factors do not give you the advantage for you to make the maximum earning, you may wish to consider creating your own node and a private mining pool.