Go onto wigan and Leigh service area website there is some defensive drills on there.

3v2 on a small pitch, i use it all the time during our sessions makes players think more on position and technique, it's also good for your attack so kills two birds with one stone, confidence is the biggest issue with tackling so the more they try the better, i also use a10x10 grid and have each player making as many tackles as they can in 60 seconds with so many in the area theres always someone near enough to get at, ultimately just try think up your own ideas you'll be surprised what you can come up with, good luck!

Depends what age group and what league they play in etc.

There can be different drills for different types of teams and with a bit more info we might be able to help!

Make sure the players individually have the basics in place with regards to there own tackle techniques, i find more often than not if players are shooting out they tend to be weak tacklers and will also be stepped pretty easily by players as the tackler does not know or understand to slow down and adjust his footwork just before contact.

My advice is always work in small groups of 4 or 5 when going through line drills, a good one is a figure of 8 drill and it tends to get players shuffling left and right, back and in and working together.

Repeat the drills over and over again, try doing against the clock or with an added challenge.

Not sure what age group you will be coaching, but they are older lads then you will need to drum it home that you need to get rid of bad habits and quickly

Give the kids tennis balls to hold. That way they do not grab when tackling