Back when I was rated around 1700, I discovered that, within reason, the fewer moves I looked at and the less deeply I tried to calculate, the better I played! By only considering the first 2-3 moves that occurred to me and looking 3 or 4 moves deep my play seemed to be more incisive and resulted in fewer blunders.
As has been pointed out in a couple of previous posts sometimes it is not always necessary to try and calculate a lot of moves ahead. I think there are a couple of reasons why this is a good idea for amateurs to play this way. First of all, if you have played over a lot of master games, you should have developed some measure of pattern recognition  and you can allow your subconscious be your guide. Another reason is that trying to calculate a lot of candidate moves and their variations plus remembering the results of those calculations more often than not leads to a bewildering array of moves you have to keep track of. The result is often confusion. Another reason is that among amateur players there is often a good chance your opponent isn’t even thinking along the same lines as you and the result is a lot of wasted effort looking at moves you’ll never play because your opponent played something you never considered.
Of course I am assuming you are playing solid positional moves and not making a lot of tactical errors in your play! When you get into a tactical situation you usually must calculate concrete variations, but even then be careful about looking at too many moves too far ahead.
If you have ascertained there are no tactical possibilities then you can often go ahead and play your move without any calculation because there isn’t any forcing replies to worry about and your opponent likely has a wide choice of replies anyway. In fact it may not even make any difference what his move is. Of course because you are being guided by general principles, there will always be exceptions but often if you waste a lot of time looking at second and third best moves you will end up playing them; I’m not sure why that is!
In My Great Predecessors, Kasparov claimed that Capablanca rarely needed to calculate anything in his match against Frank Marshall because Capa was good enough to defeat his opponent by playing good, not necessarily the best, moves! That may be a bit of an overstatement but it illustrates the point.
I discovered that often within the first 3 moves I looked at was a move masters had considered. Maybe they rejected it but at least they looked at it. Let’s face it: rejected GM moves usually aren’t that bad!
Sometimes forcing moves may be easier to calculate than quiet moves but, as I mentioned, the task can also get quite complicated and confusing. Also, it’s not unusual when calculating forcing moves to get to thinking your opponent only has limited ways in which to respond to your forcing moves. The result is you often miss something really important.
As a general rule, when the P-structure is static and your opponent doesn’t have a lot of counterplay, you can limit your candidate moves considerably. In any case, next time you play a game, try and limit your choices to the first 2-3 moves that pop into your head, calculate 3-4 moves ahead at most and try to judge the merits of the position. Then play the move that seems the most threatening even if it is threatening only in a general sort of way. I think you may find you are 100-200 rating points better than you think! Obviously this isn’t going to allow you to beat Experts and Masters but it’ll work well against average players.
 For more information on the subject of pattern recognition you can search this Blog for several posts.