A feature not very well documented in the game is the order queue. Many people don't even know it exists.
Normally, when you issue an order to a unit, that unit will go off and do it. If before that order is completed you issue another order then the first order is cancelled. But RoN allows you to queue up orders. By holding the shift key down, any order you give a unit will be added to end of the unit's order queue. Queued orders will be done one after another when each is completed.
This largely depends on how inventive you can be. But here are some great uses.
Most players actually use this in one form without realising what it is they are doing. Most commonly with the scout you start with. It is common practice to order lots of way-points when plotting a scouting pattern. In reality, you are not doing this, you are merely queuing up multiple move orders.
Bribing units is fun, but when most people do this what tends to happen is that both the bribed unit and the spy get killed. Use order queues to save the spy. By right-clicking the target and then shift-right-clicking somewhere to move to, the spy will have a queued move order. The instant the target is bribed, your spy will run off to safety. Any other units in the area are probably dealing with the new enemy in their midst, giving time for your spy to escape, and all done without you thinking about it.
Buildings also have order queues. We all know about queuing different units to be produced in the barracks, but you can also set multiple gather points for the units that emerge, so you can get the to their gather point without walking past that fort that the enemy inconsiderately built on the straight-line path.
Holding shift down will add an order to the end of the queue, but you can also add orders to the front of the queue too. By holding the Alt key down at the same time as the shift key, the new order is inserted at the start and the new order is carried out immediately but without upsetting the rest of the queue.
Again, how you use this is up to you, but here are a couple of possible uses. Suppose your spy is off to bribe an enemy and then retreat, just as she passes your army an enemy spy bribes one of your units! Simply select your spy and shift-alt-right-click the enemy spy. Your spy will stop and shoot the enemy spy and then resume her original order. Many people use citizens to scout the corners, this can get you extra ruins as your scout does a different path. However, scouts have a nice ability to divert from their path to scoop up any ruins the spot. Citizens and other units do not have this ability and will happily wander past a ruin. Usually when you spot this you have to order the pick-up and then re-order your citizens scout pattern, a lengthy process. But all you need to do is insert the pick-up order, just shift-alt-right-click the ruin and the citizen will go get it and then resume it's path.
Many units accept orders intelligently. If you don't have use abilities as a group selected (ie. the default) then when you have a group of units that can all do a unique order, only one will accept the order. This enables you to save an awful lot of micro-management. I will use spies as the example again. You have ten spies (yes ten!) and want to cause some serious havoc in the enemy camp with mass bribe. You could select one, order the bribe, then queue the escape order and then move on to the next spy and so on. But a much easier method exists. By selecting all your spies you can right-click ten separate targets. Every time you click a target, one of your spies (only one) will accept the order, the others are not affected until it's their turn to accept an order. Then, still with all ten selected, just queue the escape order. Many people employ this multiple spy selection technique, however one problem exists. If you have orders some of your spies, say six of them, and then "miss" your target for the seventh you will over-ride the smart ordering system with an unintentional move order, cancelling all previous targets. This disastrous mistake is easily avoided with the order queue. By holding the shift key down while selecting targets to bribe, any miss-click will just be queued so you can re-click the target. Any spies already ordered will carry on and just treat this as an extra little move order (they will be near there anyhow) and any spy not yet ordered will move there first before bribing, again, in the local area. All will then make their escape with the final queued up escape movement order.
This ability works for a number of units and buildings to save you a lot of micro-management. Special ups can be sent to multiple targets, as can cruise missiles.
What you do with these order queues is largely up to your imagination, I am sure that there are some really cunning uses that have not been thought of yet. Hopefully, if players start taking advantage of this great feature in RoN, more great tricks can emerge. Because of the complexity of interaction of all the different units in RoN, the orders don't always work out as you may expect. Experiment to see if you can use the queues to support your play style. Anytime you find yourself wanting to do several things with a unit, think order queue, the more you can use them, the less you will have to remember to do with any unit later in.
How about constructing buildings, guarding units, general abilities, directing city and tower fire, air missions, besieging economic targets in a well defended city, killing multiple siege with a squadron of LC, targeting all HI in turn with your FA, better control in killing citizens with your raiders...