Let's start by trying to identify what are classically the most important of these bases, the five aggregates or skandas. In the Heart Sutra it says, "He looked and saw that the five aggregates are empty of inherent existence." So if you don't know what these five are, how can you look into the ultimate truth of them?
The five aggregates are: a great heap of physical things, a great heap of feelings, a great heap of discriminations, a great heap of created things (Sanskrit: samskara) and a great heap of awareness.
So then, one has heaps, aggregates, and these locate living creatures. Let's take the aggregate of physical things, which can be further broken down into the external objective physical things and the internal subjective physical things. Sights, sounds, smells, tastes and sensations are the external or objective physical things in this great heap of physical things, while the five senses are the subjective or internal physical things.
The second heap is that of feelings. What are feelings? They are the experiences one gets out of things: pleasant experiences, neutral experiences and unpleasant ones.
The next heap is discrimination, which is defined as that part of the mind that functions to identify particular things as what they are.
The fourth aggregate of created things has most of the non-associated created things. It's a catch-bag for everything not included in the other four heaps.
And what is the fifth heap? This is all our awarenesses or consciousness or thoughts. This is generally looked at as sense-based awareness coming from a thinking mind.
One can only focus on the reality of emptiness when one has seen the size, the dimensions, of what one is refuting or denying.
The Tibetan saint Tsongkhapa said, "Anything that is produced from conditions is never produced." You can unpack this apparent paradox in this way. What you are saying is that nothing is produced as something that is independent; nothing is produced as something that is there under its own power. That's what you are trying to demonstrate.
As the great Aryadeva said, "Anyone who gets a view into one reality gets a view into all realities." What he is saying is that if one plumbs the depths of reality of anything, one doesn't need to go through the whole process again with another object. Just bringing to the mind the reality you've seen in one object or person, and turning the mind to another, you will look at its reality as well.
That's why every one of our sadhanas without exception starts with the mantra that means "Om, this is purity, all Dharmas are pure, I am that purity." Before doing any sadhana one brings to mind this fact of the ultimate reality—of emptiness.
http://www.lamayeshe.com/article/two-truths