It is a tradition for a Buddhist to go to the Bodhi Tree to make their aspiration.

But what did they aspire and how they did it?  Some would offer something to the Bodhi Tree before their aspiration such as milk, lights, etc. And they wish for material and worldly gains such as wealth, good health and happiness.

What is the true perspective of making aspiration?

Let us go back to the time just before the Buddha's Enlightenment under the Bodhi Tree. There was this lady named Sujata who has just got her wish fulfilled after making her request from the Bodhi Tree.  She came back to offer the milk-rice as a repayment to the Deva of the Bodhi Tree.

At the same time our Bodhisatta Gotama also made his aspiration that he will not raise from his seat until he attained enlightenment to the quest of Truth he was searching.  He then selected the Bodhi Tree as the venue for his meditation.

That is when Sujata mistakenly thought that the Bodhisatta was the deva of the Bodhi Tree and offered Gotama his last meal. He then strived on to attain enlightenment on the Vesak night.

Now what is the right method of making aspiration?

Aspiration is NOT making WISHES!
A Buddhist makes aspiration to re-focus his spiritual strive towards Enlightenment.
Aspiration should be carried out after (and not before) one has performed a meritorious deed such as Dana (generosity).

“By the power of Truth from these meritorious actions of mine, may I continue to have opportunity to learn the Dhamma, to practice them and to realize them until I attain Nibbana.”

One may aspire for worldly gain with the objectives to support his/her spiritual strives. 
 “With this healthy body, may I be able to continue to help and assist those who are in needs”

As the year is coming to the end, everybody is making their new year Resolution.
We as Good Buddhist shall make our Aspiration too.

Let us focus our good merits to achieve more meaningful actions that will contribute to the well being of both others and our self.

By the power of Truth, may you continue to track the path of our Master – Gotama the Buddha.