If your playing online poker ring games without using Poker Tacker or Holdem Manager you are definitely giving up an advantage, especially if you are playing multiple tables. I am a very statistics orientated player, I understand that statistics can not tell you everything about a player but they can go a long way into telling you almost everything about a players tendencies. You just need to know what stats mean what, how to best exploit your opponents stats and also how many samples are needed for the statistics to be valid.
To get a basic idea of your opponents most basic stats IE there preflop VPIP (Volume put in the pot) and PFR (Preflop raise percentage) you can get some kind of vague idea after perhaps only 50 hands. This will be enough to tell you roughly if this person is a fish or a regular. However, over only 50 hands, the usefulness of nearly all other stats will be marginal at best.
To get an accurate idea of someones preflop 3-bet percentage you need roughly 500 hands, to get an idea of there positional 3-bet percentage you might need 1500 hands plus.
To get an idea for players postflop tendencies, for example aggression frequency based on street, I would say you would need at least 200 flops to get an accurate sample but can get a basic idea with less samples. The same goes for raise flop percentage, continuation bet percentage, 500 flops would be great but you can get some kind of idea over about 100 flops or 500+ hands.
A HUD (or headsup display) are the onscreen statistics that appear on the other players. Most players have a main HUD which shows a few choice statistics and a popup which when clicked shows more detailed stats about a player. On my main HUD I have the following statistics:
When I click on the players HUD and get the second HUD of more detailed stats the most important ones I believe are the following:
3-bet percentage depending on position: I like to check this to see how much a player is 3-betting from early/mid/late position and from the blinds. Most good players will have different stats depending on position and having these at your disposal will allow you to quantify there 3betting range.
Fold to continuation bet percentage: I like to use the fold to continuation bet statistic to get an idea whether continuation betting is a good idea. I obviously pay attention to things such as board texture and other variables that determine whether a board is good to continuation bet but also take into account there fold percentage, so against people who fold a small amount I will avoid continuation betting my air hands.
Continuation bet percentage: I look at this percentage when deciding whether to carry on on the flop. If I am playing against a player who continuation bets a lot, I may consider calling his bet with a wider range on the flop or bluffraising it with no hand at all. Remember, alot of players who continuation bet a lot, also bet the turn a lot, so its not wise to float the flop bet with no hand and then fold when he double barrels the turn.
Fold to turn/river bet percentage: I use these stats relatively often, some players may have low fold to continuation bet percent but fold a lot to turn and river bets, if you encounter these types of players
Aggression frequency based on street: I look at players flop/turn/river aggression frequency. What this does is tell you how often a player is betting the flop/turn/river. Players with over 50% aggression frequency tend to be pretty aggressive. I can use this statistic as a gauge to whether I should fold, call or raise a turn.
Checkraise flop/raise flop percentage: I look at this statistic often before deciding whether to continuation bet a flop. The reason I do this is to see if they are someone who raise or checkraise a flop with a high percentage, against people who do this I will consider checking behind some marginal hands, or bet the flop with the intention of proceeding based on a raise.
4-Bet percentage: I use this statistic to quantify how wide someone is 4-betting. People with a high 4-bet percentage are either 4-bet bluffing alot or 4-betting wide for value. Players who a small 4-bet percentage are rarely/never bluffing and usually have one of the top holdem hands when they 4-bet.
Fold to 4-bet percentage: I use this statistic when I get 3-bet to quantify how effective a 4-bet bluff will be. I use this aswell every players position in the hand to figure out whether a 4-bet bluff will be 1) profitable and 2) believable based on our recent history. People with a fold to 4-bet percentage of higher than 60% are vulnerable to be exploited by 4-bet bluffs.
W (Won $ when saw flop percentage): A very wise player Aaron “aejones” Jones, once said, a true reflection of a players skill is there W multiplied by there VPIP. I use the W stat to get a vague idea how good someone is postflop. Players with a high W frequently have high aggression frequencies and bet in good spots and barrel in good spots.