Draws
Knowing what your hand is after all seven cards (5 board cards + your hole cards) are revealed is simply applying the rules of the game. More strategic is knowing what your hand is likely to be before all the board cards are dealt.
Made Hands
A "made hand" is a hand where you have made at least a pair using at least one of your hole cards. For example if you have Ah Kc and the board is [Kd 6c 3h] then you have made a pair of kings. You have a strong hand already and while you'd like to improve (to three kings for example) you feel that as long as the other players don't improve you likely will win. Hand strength is a measurement of how strong your made hand is.
Drawing Hands
A "drawing" hand is the opposite situation. You do not have a made hand and feel you must improve in order to win. Knowing how likely your chances of improving are is an important consideration when you decide whether to continue the hand or fold. For example if the board was [Kd 6c 3h] as before and you hold 5 and a 4 then you have a chance to improve to a straight if either a 2 or 7 lands on the turn or river (this is called an open-ended straight draw). If you have a Queen and a 9 then you can also improve to a straight, but you need both the turn and river to do it for example Jack on the turn and 10 on the river (this is called a running inside straight draw).
In the second case you are much less likely to improve to a straight and you would be said to have a worse drawing hand. Thus you would be more likely to fold the Queen and 9 than a 5 and 4 in this situation if you felt you were behind and needed to improve in order to win.
Calling with draws is more common in fixed limit poker as you know there is a maximum amount you will have to pay to try and make your draws. In no limit poker draws are more often either folded, or bet strongly as a semi-bluff with the idea that even if you are called you have a good chance to win.
For some examples of draws see our draws section in help
Positive and Negative Hand Potential
In addition to looking for and seeing your own draws, it's important to try to see what kind of draws your opponents could be playing. Poker Academy takes draws into account by showing you your hand potential and negative hand potential (the number in brackets) in the sidebar. Your hand potential is the chance that your hand, if it happens to be behind now, will improve to be the best after the next card is revealed. Negative potential is the opposite; if you are ahead what is the chance one of your opponents will overtake you. Note that these numbers are the chances for the next card only. On the flop, if either the turn or river could improve your hand you can approximate this by doubling that number. It does not take into account the situations on the flop where you need both the turn and river to improve. You can refer to Poker Academy's calculation to check your own mental approximation of how strong your potential is.