Consider the Order of Play
This is probably the most important final thought before playing to the first trick. Once you've counted how many extra tricks you need, and decided which technique/s to use, the last question is which order to play the cards in. There are a number of considerations:
(1) If you're in no trumps, think about whether you need to duck a trick in the beginning. The reason you might do this is to break the defenders' communications.
Let's say they've led the ♥4 and you hold the ♥102 in dummy, and in your hand ♥A97. You know they've led from their long suit (fourth highest) and could have four or five hearts in their hand. The layout could be this:
If you win the ♥A on the first round, East will have a heart to return to partner if/when they win a later trick, and you will lose four tricks in that suit. Even if you win the second trick, East will still be able to return a heart. If you don't take the ♥A until the third round, East won't have a heart left to return to partner. This is known as a "Hold-up" play, and is one of your considerations about when to play a particular card.
(2) Are you able to draw trumps at the start of the hand? If you have enough tricks for your contract, draw them immediately, but if you can't afford to let the opponents in, because they will take tricks of their own, delay the drawing of trumps until you've trumped losers in dummy, or discarded losers on winners. Often when your side does not hold the trump Ace or King, don't draw trumps straight away.
Or if you can't see enough tricks for your contract by playing two trumps at a time, and you need to make them separately, then don't draw trumps. On about half the hands you play, you shouldn't draw trumps until you've reduced losers in other suits.
(3) Another consideration is listening to any bidding done by the opponents. If one of their hands is strong, (say they've opened or doubled), expect points to be there. Play suits in a way that takes this into account. If their partner has passed throughout, they will have fewer than six points.
(4) The final, and vital, consideration in your plan, is how to reach the winners after you've developed them. There's no point counting cards as winners if you can't get to the other side of the table to take them! This means considering entries. There are two types of entries; external entries (in other suits), and internal entries (in the suit you're working on). If you keep trying to do this, it will eventually come!
What's an Entry
An entry is a way (usually using two cards) to allow you to cross between your hand and dummy. Sometimes the entries are right there and obvious, but at other times, declarer must create the entries needed. An entry is usually a high card, but it needs a lower card (a link card) in the other hand to cross over with.
Sometimes you need to create an entry to a particular hand, and at other times you need to preserve an entry. This is especially critical in no trumps when the weak hand has the source of tricks, and there are not many big card points to allow you to win tricks in that hand.
Looking for more information? These books will help you learn the basic skills required to play bridge.