In live poker games, some amateurs will wear sunglasses, hats and scarves to try and hide their physical tells. They “hide” to keep their opponents from seeing their jugular vein pulse or their pupils dilate. They are afraid of pro poker players - or even good amateurs - seeing through their bluffs and monster cards. Their strategy isn't necessarily wrong, they are simply focusing on minutiae while big picture concepts elude them.
The Truth Is
Most beginning players make so many equity errors with early bet sizing that physical tells have very little impact on their wins and losses. By the final betting round, the pot odds often dictate the calls and folds, not that bead of sweat running down your opponents forehead. Online there are even fewer tells; timing, bet sizing and player history/tracking are the tells we will talk about today.
Online Tells
Timing is obvious and simple but can be an effective move to utilize when playing online. By using the time you take to respond to your betting turn you can influence your opponents next move. In live poker this is referred to as hollywooding it, making an easy decision look difficult and sometimes agonizing. This is a basic move that players must understand both sides of in order to gain an advantage.
Merging Ranges
Figuring out how to merge your betting ranges is crucial to playing high level online poker. This is a fairly easy concept that sounds fancier than it is and a lot of players already do it without giving a name to it. You simply have the same bet sizing for your value bets as for your bluffs. If you can merge your bluff range and your value range, your opponents will have a difficult time figuring out your hand and will fold when they should call and call when they should fold.
Once you are able to effectively merge your ranges, your hand history will tell no clear story. If you run a heads up display - or HUD - of a good professional players actions, you will find that their value ranges and bluff ranges are nearly identical. This gives no tell and that is the whole point of merging ranges. When you find a player online with the opposite - a polarized - range, it's easy to exploit and they become your delicious fish and chips!
Every poker hand is a story. Better players know how to keep the story going and when to close the book. I tell my stories 
Have a lucky day!
