Updated: Feb 7, 2020
The waiting element would seem to be the most reactive of the Observation types, where the Learner just sits back until the time is right. While that might well work in some instances, it is not the most effective way of doing things. Being a proactive waiter, where you have considered carefully all your preparations, puts you in a much better position to succeed at this kind of observation. You are priming yourself for success.
Firstly, the Learner has to be very clear about what (or who) s/he is waiting for. It is just as important here as it is in Search to identify the key features of your objective. If you cannot identify clearly the main characteristics, you are much less likely to be able to spot it when it does appear. What do you know, remember, or can find out about your target object? There's a Forget-Me-Not that you might want to use here: Remember Research Remember.
The three Rs of Remember Research Remember are helpful because they remind you to try and remember everything you know on this topic already. This Memory activity primes you for any further research you may do (which could involve Reading Effectively, of course!) so that you find relevant new information more readily, and remember it more effectively as you can make connections or links to previous knowledge. This might involve finding out more about the target item's habits or behaviours as well as just a physical description, while another thing to research might be habitat (Places would be a helpful Forget-Me-Not here).
For instance, suppose you were a bird watcher and were trying to spot a rare bird. Quite apart from knowing what the bird looks like (did you know that already, did you have to look it up, or did you ask for information from a fellow Twitcher?), and remember you might only see part of the bird if it is hidden in the foliage, you would want to know things like whether your target was nocturnal, diurnal or crepuscular. After all, there would be no point sitting waiting for your rare bird at high noon if it prefers the soft light of dawn. The corncrake is much more commonly heard than seen - but if you know what it sounds like, then you can be ready with your search patterns to try to be one of the few people to spot the bird itself.
Waiting is also strongly linked with the Memory technique of Flame, Fuse, Fire! when you are waiting for a particular location, time or event to help you remember (to do) something. Again, preparation is key. Think about what you are waiting for, and what it will help you achieve, to make sure that it happens.