1. Compare the different scores available to me.
2. Seek out professional recordings.
3. Print the music as I will be marking it up.
4. Study the form and phrasing of the work. Sometimes, as in the Telemann I will mark in the phrasing.
5. I will consider the era in which it was written for clues on possible interpretations.
6. I translate any unfamiliar terms I find in the score.
7. I might consult other sources to explore the style and era of its creation. For the Sonata in C, I enjoyed re-reading the section on Haydn ornaments in the book below.
8. I will listen to multiple professional performances and mark on the score ideas of interest. I often will slow down a recording to hear how the artist plays their ornaments.
9. I might consult with a colleague or my piano coach as well.
In short, I will have a clear set of ideas, those I discovered and my own, to explore as I now start to "learn" the piece. I will share these with my students.
If I can help you discover intriguing world of classical music, please call me.