You're right, the most important restraints are those preventing forward movement. There are a whole multitude of different ways to secure a vehicle safely - here are just a couple of ideas I find work well for me.
Important not to ignore possibility of sideways movement - strike a balance between critical restraint in direction of travel and sideways restraint.
I always use similar restraint at the front as the rear, as this keeps even tension all round, thereby minimising any forward/backward oscillation caused by stretching restraints. It also has the advantage of controlling sideways movement better than uneven front/rear tension.
Keeping the angle of restraints more horizontal than vertical minimises the load on the restraint under braking -meaning less stretch if using fibre (ratchet straps) and thus less movement. Angle can be reduced by cross-mounting restraints as in diagram. If the load space is long enough I might put the rear restraints to the rear and front to the front - but often where space is tight the angle can be kept low by mounting as per diagram.
Whenever possible I attach restraints to the axles, as this allows the chassis/ body to roll on the suspension without affecting the restraints. It is amazing how much a vehicle will roll on its suspension, causing uneven loading on the restraints.
For example someone once moved my Bedford MJR by pushing front wheels hard forward against bulkhead of a stepframe trailer (good policy), but then just put a chain and load binder (over-centre tensioner) over the rear NATO tow hook, with chain anchor points slightly forward, thereby holding the truck forward against the bulkhead. Within 2 hours the NATO hook, although softer than the chain, was well on its way to cutting through the chain due to chassis roll!