For many beginners, the myriad of choices in any given chess position can be overwhelming. Attempting to analyze every possible move takes way too long to be a practical approach, but novices often try to do this (usually unsuccessfully). A better approach is to limit your analysis to a few candidate moves.
Candidate moves are those moves which, at first glance, appear feasible in a position. For instance, if your opponent looked to have a strong mating attack against your king, you would only consider moves that prevented that checkmate without losing so much material (with no compensation) that you would surely lose anyway; spending time analyzing any other moves is a waste of time, as we can be sure they are losing no matter how deep we look.
Usually, things are not quite that clear. In a typical middlegame, a novice may have a difficult time deciding what moves should be a candidate and what moves shouldn't be considered. You should normally take the time to give a look at all your checks, captures, and threats, as well as those of your opponent. These moves tend to be forcing, and may help you find interesting (or necessary) candidate moves. In positions where no tactics are obvious, candidate moves will generally be those that improve your position; moves that take a bad piece to a more active square, or which increase the pressure on our opponents (or relieve the pressure on our position) are likely candidate moves.
As you improve your analytical abilities, your ability to select candidate moves will improve. For now, the important point is that you are not deciding what move you want to make at this stage, nor are we spending a lot of time looking deeply at any one choice. Our goal when selecting candidate moves is simply to narrow our choices to a few potential moves (sometimes as few as one, sometimes many more) that we want to analyze in greater detail.
Only when we have selected our candidate moves are we ready to start calculating variations and looking deeply at our potential moves. By narrowing our choices this way, we significantly reduce the time it takes to find what we think is the best move, because we're focusing on just a few choices, rather than spending time wandering between dozens of moves -- some of which are clearly bad. Once you have narrowed your choices, stay within them and only analyze the candidates you've chosen. If your analysis turns up an idea that makes you think another move should be considered, or if none of your current candidates are satisfactory, then you can always add new candidates to look at, but for the most part you should be focusing your thoughts on the candidate moves you selected earlier. Finally, after analyzing your candidate moves, you can pick the move that you think is best.
This method of thinking about chess may be difficult at first, but with practice it becomes second nature. Using candidate moves is a major step towards thinking like a strong chess player, and helps make the nearly infinite possibilities in a chess position seem a lot more manageable.