There is no such thing as a "winner" (apart, of course, from the elusive big cross-court nick. Generally - if we are honest - a phyrric victory achieved at a substantial net cost, not benefit, over time). Look to play "good shot", "good shot", "good shot" and then - as the gaps get bigger - one of these "good shots" will become a winner. You cannot go from nothing to a winning shot over-quickly. It doesn't matter if the rally continues, as long as you are not doing the running. Rallies will get shorter as you impose your tactical superiority.
If there is a huge gap, hit the ball into it - even if it is the obvious shot. A typical scenario is where you have played perhaps a good drop or boast and the opponent has hit the reply very wide cross-court off the side wall (or side and back walls) and it has come back to around the middle or middle-deep of the court.
The important point here is your early movement. As soon as you see where the ball is going to finish, start moving back (and with an early full backswing) to completely establish your dominant position on the court. (Some "experienced" players may even back off into the dominant position more than necessary and move in to play the ball only at the last moment, thereby gaining even more positional advantage.) Your opponent is now stranded behind you in a very weak position with nowhere to go, you have room to play the shot (if you have not moved into position early you may end up playing it a bit cramped, or having to play a let when you had a clear winning position) and you have a huge gap to play into. The secret is to actually play into this gap. Forget delay and deception, the hard work has been done. Even though your opponent knows where the ball is going, you know that he knows where it is going and everybody watching knows where it is going, it is still the right shot, virtually every time.
You can hit it short or long (as long as the narrow angle is right). A hard lowish drive is normally best. It should be the final "good shot" of the rally. This rule does not apply where the ball is around the middle of the court but in front of the centre line. In this more forward position, the opponent can come around the back of you to a more central and tenable position.
In this case, more deception is appropriate - probably dummy drop/but drive or dummy straight/but cross-court drive. (A drop from central court positions is dangerous because the angle is very wide, not allowing the ball to be tight at any stage - except for the unlikely nick. Too many of these wide-angle drops, or played too soon, can turn a position of being 80/20 up to being 80/20 down in a second. The risk is not worth the reward).
Hit more deep drives than you think. On the backhand hit more straight than cross-court. On the forehand hit about 50/50. Obviously, when the ball is tighter, the proportion of straight shots should go up. Playing deep (particularly straight) is not negative: it is the crucial basis of the whole game. All other shots derive from - and depend upon - good deep drives. Low risk high reward.
The lower the standard of player, the more boasts are played. It is a loose attacking shot and must be played relatively sparingly. A good boast will certainly damage your opponent but a bad boast - or even a good one played too often or too obviously - will damage you more.
The Key Shot - The best safe attacking shot - after the drive - is the straight drop. This is a very, very important shot. It can and should be played not only from the front but - more importantly - from deep and mid court. As long as it is played at the correct angles it is a safe attack and will force a loose reply enabling you to easily play another good shot, probably deep. This drop shot is particularly important when you are on the backhand side towards the back, where much of the rally action takes place. Good risk and reward. More difficult and risky to play on the forehand.