The top 10 tips are as following:

1. Hit the neck joint
2. Hit the neck joint
3. Hit the neck joint
4. Hit the neck joint
5. Hit the neck joint
6. Hit the neck joint
7. Hit the neck joint
8. Hit the neck joint
9. Hit the neck joint
10. Hit the neck joint

xD
Just kidding, but it really is a good idea to hit it. If you want points, go for the
head. If you want a decap, go for the neck, hard. Although the neck is fairly
easy to dismember, you'll still need some force to do it. Use as many joints
as possible to add to your momentum, and time your kick/punch correctly,
and it shouldn't be too big a problem. But hitting the right place is another matter
entirely. Punches can be a little tricky because your hands are cubes, but that
can be solved by grabbing or hitting from behind. Kicks doesn't have the problem
with your feet being cubic, but there is just the little matter that your feet
is on the floor while Ukes head is 2.5 meters in the air. But with a little jumping,
that shouldn't be a problem.

P.S. Power to the blocks of text ಠ_ಠ