THE BROADBAND METHOD
There is no point learning this with concentration and will power, they are forms of focussing. Starting off with an appropriate use of the senses, is important, the ability to switch it on.
We need only look at a pidgeon or blackbird while eating and notice how quickly they can change between their focussed mode of seeing and their broadband mode. They are so familiar with broadband seeing that the second the head is up, is enough to register if anything dangerous is moving.
At first, it's important to do this for only a minute or so at a time. If you want to make it a priority, then do it five times a day, one minute at a time.
There are lots of reasons for starting with just one minute a day. Partly because if doing this - even trying to do this - is enjoyable, then you will want to repeat it. Partly to create a feeling of urgency - it's got to be done now, and in a minutes time it'll be too late. And partly, to realise that you can turn it on, any time, without doing anything to prepare for it.
Your subconscious knows how it feels to use the senses like this. A minute a day which is interesting or enjoyable is the best way to give your subconscious the signal that it's time to remember.