Match re-starts (at the outset, after half-time and after tries) are executed with a drop-kick at the centre of the pitch.
All kicks, other than try conversions, must be from hand.
Try conversion kicks may be taken using a place kick or a drop kick. Kicker chooses the position in front of the posts i.e. the kick does not have to be taken in line with where the try was scored.
Loose balls on the ground may not be kicked (no 'fly hacking').
Kicks may be made during open play.
Penalty kicks for goal are not allowed.

Scrums

3 front row players and two back row players (locks).
Locks bind around the outside of the prop's hip, not between their legs.
Engagement sequence is crouch-bind-set.
Ball must be fed straight into the tunnel.
Defending scrum half may stand at the tunnel on the same side as the attacking scrum half, but may not advance beyond the centre-line of the scrum.
Maximum push / pull distance towards either try line is 1.5m. Maximum wheel is 45 degrees.

Lineouts

Extend from 2m to 10m from the touch line.

Open Play

Hand offs / fend offs are not allowed.
High tackle line is the armpit.
Scrag tackles are not allowed.
No squeezeball.

General Regulations

The relevant Law is Regulation 15 Appendix 1-D (available on the RFU website)
Ball size: 4
Maximum pitch size: 60m x 43m + 5m for in-goal areas. A 15m line should be indicated (analogous to the 22m line in the adult game).
Match duration: Festival - 7 minutes per half; Single fixture - 20 minutes per half.
In general, when the offside line requires 10m in the adult game - the equivalent is 7m in the U11 game.