Pay Attention To Everything
One of the biggest mistakes a new poker player makes when playing Texas Hold em is that they concentrate on what cards they have. This will severely reduce the amount of leverage you have when it comes to winning the pot, if you have a bad hand you are basically hoping that everyone else has a worse hand or folds.
A simple Texas Hold em poker tip that I recommend to every new poker player is to be aware of whats going on. Pay attention to the cards on the table and your opponents this goes for every style of poker.
When each flop has been dealt have a think of the best possible hand you could make from that, keeping in mind of any straight or flush possibilities. Keep doing this when a new card is revealed and you will have a better idea where you fit on the best hand scale.
Being aware of how your opponents react to certain situations will give you a huge advantage when it comes to taking the pot, even if you are not playing you should be analysing each player to see what subconscious signals they give off or if they follow a certain pattern. You will agree that its much harder to spot this type of thing playing online poker but it still is possible, you just have to go on their betting behaviours opposed to what they are doing in person as you cannot see them.
For example if you were watching a game and a player always seemed to fold on a re-raise on a river, you can implement that into your tactics against him/her and take away the pot regardless of your hand. Having as much information on your opponents will make it easier to determine how to play your game, you should never follow a set of rules when it comes to playing poker.