TDW - Best practices

It's better to make no defence than make a trash one

If you don't know how to build defences, just observe experienced defenders or better yet - read this wiki, because you may observe the wrong "experienced" defenders. Listen to other defender's advice and if you think it's reasonable apply it onto your defence and contact me, so I can add it to the wiki

Building a bad defence is truly annoying, because if an experienced defender joins, trust me, they will not break your defence to build a good one, that's just way too much effort. This has happened to me so many times, when I was afk for a moment at the start of the game or I had to gather the required resources and someone already started building some trash wall

No crafting tables under floor pattern

This is probably the most common mistake people make and I've seen it SO many times.
Fill the floor with crafting tables before building the pattern, it's not that hard

Don't put iron bars on the edges of your wall

Don't put iron bars on the edges in middle column of your wall. Why? Because iron bars are not a full block, rushers can just break one crafting table and easily neo around the wall, if you use full blocks there they will have to break two blocks, which is more unlikely they'd try to do

Don't leave water on the edges of your wall

Don't leave water on the edges in middle column of your wall. Especially if combined with iron bars (first wall in the image), this is just totally wrong. But let's say you built it like the third wall in the image, the rushers can again just break one block and neo

Use corner stairs while building a staircase

Corner stairs make little holes in your staircase, which allows you to see what happens under the staircase and therefore you can detect whenever someone is griefing it from below

Make sure your defence is unboatable

Whether it is a wall or a floor pattern or whatever, rushers shouldn't be able to boat into places that may give them an advantage.
(boating on the on-wall pattern isn't usually a big deal, however boating around the wall is)

Don't build your walls IN FRONT of the bedrock walls

Build your walls on top of the bedrock walls, refer to the subsections about walls placement

Extend your walls to the bottom of the map if they stick outside the bedrock walls

Please, it's not that hard and prevents rushers from hiding under the wall, so snipers can't shoot them from the snipers' nest, which can really ruin the match, because then the snipers have to drop on said rusher and they may not survive the melee fight (happens to me all the time ;-;)

Don't. use. wooden. pressure. plates.

There's no reason to use wooden plates when you have stone, iron or gold ones available. Pressure plates are often placed on wooden materials like fences or crafting tables, so using wooden plates removes the necessity of switching tools when the rushers are trying to break through your defence. You're also wasting wood that could've been put in better use - to for example craft fence gates, which are pretty wood-intensive to craft

Some defenders believe using iron plates gives rushers some sort of camouflage, because they usually wear iron armour, however I do not think that is a big deal, just pay attention to your woolroom path

Put closed fence gates if your front pit base increases in height

This turned out to not be so great thing to do, as the fence gates can help rushers with blocking-in, so defenders can't attack them

If your front pit's bedrock base is not the same height, it's good to put closed fence gates two block above ground a block before the bedrock base increase (see the screenshot). This makes it impossible for rushers to jump and it may take them a while to realize there are fence gates above them. It's truly superior when combined with some floor pattern. I've noticed this strat when I was defending and I was keep getting stuck whenever I was travelling through my team's front pit

Don't use buttons or levers

Buttons and levers can be easily broken with water, don't use them if you don't know how. An example of correct buttons use is the Sign/Button on-wall pattern, in this pattern the usage of buttons actually helps. There are many other blocks you can use instead of buttons for most things. A common replacement for buttons in most cases are signs

Don't defend after someone got into your woolroom

You had your chance to defend and you failed. Don't waste yours and others time prolonging the game. There's nothing you can do unless the rusher who got in is some newbie or a troll. It is not possible to effectively defend if someone is in your woolroom, because: you will have to constantly check whether they're not trying to get away, they will constantly shoot at you, they will destroy your defend, they will hide inside of the woolroom or eat their infinite gapples when you try to kill them and, trust me, there will be way more rushers incoming. The only thing you can do in such situation is delaying said rusher, so he doesn't get away and hoping your team caps the wool first, but I don't know why'd you do that, do you really want the win that much?

DON'T TAKE WATER FROM ON TOP OF THE WALL

If someone places water on top of the wall and goes down, they're going for resources. Don't steal the water, it literally causes no harm and will just annoy the person who's coming back with their resources, because they'll have to tower up or beg someone (if there is someone) from on top of the wall to drop them water. Do not ever do this. If you do this to me, I'll mostly likely leave the match or stop defending

Always defend left woolroom!

It's an unwritten (till now) rule of defenders to always defend left woolroom. On most asymmetrical maps the left woolroom is just better for defending. On symmetrical maps people do it, because it's become the standard. If you defend the right woolroom people will probably think you don't know what you're doing or that you're so dedicated to defending, because no one would ever choose to defend right out of their free will. There are some asymmetrical maps where right woolroom is better for defending, for example Istana CTW by DerStiv; I guess you can defend right on maps like these, but I haven't tried it personally

Don't put more than 3 fences/iron bars on each stair while building a staircase

Watch the staircase tutorial and pay attention to the part where I place iron bars and fences. I put 3 on each stair, that's the amount that allows us to freely travel on the staircase if we make a second layer and it will prevent us from falling 50 blocks if we accidentally fall into this gap I marked with a red arrow when running up the second layer

Don't overextend the anti-sky without breaking helper-blocks

Pretty obvious rule; never underestimate your enemies by thinking you can just extend the anti-sky infinitely and they won't take advantage of that, because they most likely will! If you're not able to effectively break the blocks, because you're extending the anti-sky, tell one defender from your team to stop whatever they're doing and help you, because anti-sky has probably a way higher priority

Don't use iron blocks in your defence

Iron blocks are as hard to mine as redstone or emerald blocks, so you may think that they can be used interchangeably. However, iron blocks can be used to craft iron armour and maybe other useful things. So, if you use them in your defence close to the woolroom and your enemy without an armour gets into the woolroom, they may be able to break the iron blocks from your defence and craft armour. It's not uncommon for rushers to rush without armour if their team doesn't have an armour station or dispensary, since they die quite a lot. If you do not have any other resource blocks than iron, then you can use anvils or filled cauldrons as an alternative (Filled cauldrons are only hard to break on 1.17+, so it's risky to use them).

Make sure your defence is GOOD

Read the wiki

The Defender's Wiki - Best practices / Common mistakes