You can usually categorise beginners into two sections – the competent ones and the amateur ones.
The competent players in online poker
The characteristics of a competent beginner are fairly each to spot. They simply grab an entry-level online poker strategy book, read the first chapters and distinguish which players fit best at the table. They will consistently be bet-sizing, playing tight hand ranges, being awfully quiet and trying super hard to take the game seriously.
You could also say that these things don’t necessarily make a bad poker player. But generally, these players player a stronger range of hands than other players and when they bet, they will do so for value. Consistency makes it easier to play against such poker players.
If these players bet and you don’t have a strong hand, then fold. If they check, make sure you bet. It’s not always this easy but that is usually a good start for playing against a competent beginner.
The amateur player in online poker
This type of player has never bothered reading a poker book and they usually play on the spur of the moment. They also are usually very eager to show off their strong hands and bluffs to other players. They are also scared of their good hand being beaten and ultimately bet largely very early in the hand.
Playing against this type of player requires a basic strategy. Wait for a strong hand and exploit their weak play. You can also switch up your strategy against these players, by tightening up when they want more action and loosening when they realise that they should tighten up their starting hand selection.