Created and written by Jangooon Original can be found on the BYM forums

Predicting monster pathing

In other words, knowing where monsters will go when they attack. This particular section refers to pathing when monsters are actually inside your base, refer to ‘Mazing’ when they are outside. Monsters will always attack the closest tower, knowing this you can create your base such that your weakest towers are always the first to die off and your stronger towers last longer. The strength of each tower and their value goes like this: Laser>Cannon>Tesla>Snipe. Try and put your snipes in front first....but not always(refer to the golden rule). You can test where monsters will go with the monster baiter.

Maze monsters for maximum damage

If you can force a drop really far from any possible targets it is harder for the attacker to predict where the monsters will go often causing them to 'branch' out spreading out the damage as mentioned above. This can be done if you have lots of extra wall blocks.
Also, depending on how uyou build a corner in a wall u]you can create a weak point that can be used to mob up the monsters at a specific location behind which you can place mines for maximum effect.
Top wall is 2 blocks thick all the way through the corner. The bottom wall LOOKS just as strong but there are 2 blocks which are not reinforced(monsters can go between blocks that are corner to corner without stopping). Monsters will always go through this wall through those 2 blocks
Proper use of booby traps

There are only 3 places where you should place booby traps, with varying priority.
1. In between towers(Low priority) :

Place mines in between towers like this.

Many people underestimate the true effectiveness of a properly placed booby trap, one or two can practically neutralise an entire wave of ichis. Each can do approx 800 damage.
But to utilise them properly you must first force monsters to mob up, this will automatically happen when monsters are attacking a tower, so placing them in between towers will make sure that the most damage a wave is likely to do is take down a single tower, after hitting booby traps, cannons and lasers will make easy work of what little hp they have left.
But, take care when placing traps, make sure that your tower coverage is not compromised or it would be all for nothing.
2. To protect Silos/TH, aka. Martyrdom(Highest priority):
Once all towers are down and out, your opponent will likely send in a looting wave, if they are smart they would send a looting wave designed to trigger booby traps without loosing too many high damage monsters(finks along with octos/bolts, or DAVES), but more often than not they will just send finks. If you place booby traps around your Silos/TH where monster are likely to go, you will quite possibly ruin the attackers looting wave, expect hate mail.
3. Within entrances(Lowest priority):
Any spare booby traps should be left within your entrances, they won’t do too much, but they will likely weaken the first wave.
Deceptive tower placement:
Attacking any of the towers, all 4 will be within firing range.

Once all 16 towers are placed down, it will be very hard for the attacker to know just how many towers are within range of his target point.
This may force him to underestimate your bases defensive capabilitys and send in weaker monsters, or he may attack a point which looks to him the weakest, when in fact it is your strongest point. If you’re tired of never being attacked, doing this will likely get you more attackers, without weakening your bases defense.
Mazing/Deceptive mazing: Not so much an advanced tactic, but there are still many who do not utilise mazing(forcing monsters into where you want them to go with walls, I expect you to already know this). Deceptive mazing is when a single stone block wall is used, many do not realise that stone blocks count as two wood blocks, and will likely attack this thinking they will not be ‘mazed’. You may use this to your advantage in two ways, to maze monsters to a nearby one wooden block thick wall with laz0rs nearby. Or to force monsters to mob up.
Extra: Credit-Donald Harvill For extra sneakiness, hide a single wooden block in a row of stone blocks behind a tall building. People will drop their monsters expecting them to take a direct path through the stone wall, but instead they'll get mazed through the hidden entrance.
In the image below, the single wooden block is hidden behind the gray monster locker in the normal view. Tower monster attacks all along the south side of the base get mazed through the single entrance, and first-time attackers won't know that it is there.

The golden rule Protect other towers with Snipes, UNLESS, you can increase cannon coverage by putting them near the front(Refer to V-BDB designs). For the laser and tesla its always better that they are protected by snipes, as they have much lower hp.
Make sure drops are always out of tower range. A small, yet effective tip, just check the tower range on the yard planner and make sure there are buildings or walls on the outer edges of the your coverage. That way, monster will be forced to drop outside of your range, and you will maximise shots fired when they come closer.

Monster branching This is quite possibly the most difficult technique to get right, but if done properly will greatly increase your defences. This will only work if you have entrances, so if you don’t have any, you should make them now.
The idea is to place two towers of equal distance from the end of the entrance, and force the group of monsters to split up into two groups, greatly reducing their overall effectiveness and dispersing damage to more than one tower.
Heres a picture to better explain it:

Dont think it works? Heres an example of one attack against a base that employed branching:

  • 26s: 56 Ichis were flung in.
    * 54s: A Booby Trap exploded! Damaging 18 monsters.
    * 56s: A Booby Trap exploded! Damaging 15 monsters and killing 2
    * 01m 00s: A Booby Trap exploded! Damaging 19 monsters and killing 7
    * 01m 01s: A Booby Trap exploded! Damaging 14 monsters and killing 2
    * 01m 06s: A Booby Trap exploded! Damaging 14 monsters and killing 6
    * 01m 07s: A level 5 Sniper Tower was 1% damaged.
    * 01m 14s: A level 5 Sniper Tower was 13% damaged.

Both snipes were damaged and only one group of monsters were flung in, thus indicating that branching had occurred.
-Branching off branches/Triple branch... When you look really carefully, you can sorta see that they are of relatively equal distance:

The monsters are more likely to follow that blue path, as theres no real reason for them to walk down the middle of the tunnel. I calculated the exact amount of pixels of the two branched blue lines and theres only a difference of 5 pixels, small enough to be within uncertainty limits

As you can see, both towers are damaged, sending 10 crabs in there was a near 50:50 split from the branch. BUT...
The red circles are where crabs destroyed blocks, which is very odd as there was a clear tunnel right down to the towers. Some even went around to the other side, which was possibly due to inadequate mazing. What im trying to hint at, is that the monster pathing is now very, very weird. Branching is still 100% possible, but getting your branch to work exactly the way you want it is a little harder.