Positioning is very important and of course it will vary depending of the map and the situation but generally your team should try to disperse at a reasonable distance in order to block the maximum of potential places where infecteds could respawn, also to be less vulnerable to some special infecteds like the boomer.

Applying this strategy should become a second nature as holding the hand of other survivors is rarely a good idea and even sometimes it can be even more dangerous in spots like roofs against a charger.

There is no point in running too fast to fail miserably. Even if it is a good strategy to move as fast as possible with your team to reduce the number of attacks that you will receive, there is a moment where you might want to slow down things and wait for what is commonly called a "hit".
Some spots are advantageous for infecteds so if you precipitate too much the round could end faster than you thought.

Test the patience of the infected team for example by executing fake forwards steps or by walking so they will lose the information on your position after a while, this could trigger a panic attack on their side which will probably be less organized than usual. To use with parsimony or this might return against you, as after a while even if there is no event launched random hordes will come to attack you.

Too many times i see teams struggling for minutes to pick up a single teammate because they could not cooperate quickly enough, if one survivor is down all your attention should be focused toward him as soon as possible. One is helping and two other cover until our fourth is back on his legs.

Depending of their strategy infecteds might pressure you by going one by one or simply wait to synchronize their attack and try to finish the round directly, just be ready for both situations. You will have to adapt if you have more teammates down but i think that you understood the concept.

Also having the sense of priorities is important like for example if there is a teammate down and one grabbed by a special infected next to him, just help the one that is attacked and take care of the incapped survivor after. Reviewing your priorities is valid in various situations anyway not only here.

To end this chapter i will say that there is one situation where it is not particulary a good idea to apply this strategy, while a Tank fight except if you have an opportunity understand if he is far away enough of the group. Just see how it goes but if the Tank is agressive you should rather focus at shooting to kill him quickly even if you have one teammate incapped.

Some horde events will require you to wait before being able to going forward, in this situation camping in a safe spot is absolutely fine. So yes use the structure of the map at your advantage for example wait the end of the event in a room as closed as possible but still big enough to not be tight like sardines, that will limit the possibility of common infecteds and special infecteds to reach you.

Ladders are well known to be a choking point in this game and this is particulary the case on specific maps with long climbing or with possible instant death just at the exit. There is no magic strategy as it will often be a hit or miss but you can still greatly improve you chances.

Firstly as previously explained you should play with the nerves of infected team to see if they react or not, it might not work as they know that they are advantaged because they have the height on you and often survivors do not have the vision on what is happening above them.

Secondly you could try to throw a molotov in an attempt to burn infecteds as usually they will have already spawn in this situation, they will definitely move to avoid it but you never now this can work.

Finally this is the moment where you can not wait any longer you have to leave this ladder at your peril. The best thing that you can do now is to give a countdown to your teammates and climb together at the same time (by pairs) to being able to react to the attack as fast as possible.

Probably one of the less know strategy at least in public games and still quite important if you do not want the fight against the Tank to drag on, especially true if he is playing at distance with rocks with a good point of view on survivors.

Basically if the entire team is hiding behind an element of decor where the Tank can not see survivors, the player controlling it will lose progressively the control of it faster. Usually this is done after an attack from infecteds like that you can hide for a while without worrying about them.

The goal is simply to force the Tank to take risks or a second player will receive the control of the Tank and after that the computer take the relay as you probably know it. Obviously it is more easy to win the fight against the bot than a real player, or at least this is normally the case.

There are some circumstances that will allow your team to push a Tank, it consists of rushing him in a attempt to deal him damage or to make it retreat. This one is particulary efficient with T1 weapons as with T2 you will still be able to hit hard from far away anyway.

It is usually done once you killed special infecteds so the Tank finds himself alone or potentially when you suppose that he is almost dead, if you space out enough between each other and focus your shots on him this is unlikely that he will last long or even inflict you serious damage. The reason why the Tank will definitely retreat as this is the best strategy to adopt here unless your team is already low in health maybe. Even a good Tank can be caught off guard if he does not react fast enough, it can litterally change the course of a match.