This Minuet can easily sound very stiff depending on the performance. It requires a lot of ingenuity. The tempo must not fluctuate at all, so the ingenuity must be applied within a fixed tempo. Nevertheless, it's not about doing anything extraordinary; one simply needs to shape the lines according to individual interpretation.  

Factors contributing to a stiff sound include line shaping, but also if the dynamics become flat, it will start to sound stiff. Attention should also be paid to chord resolutions, among other things.  

Many performers play measures 1-2 and 3-4 exactly the same. Let's consider how to play the lines here. In measures 1-4, the melody line is written as ECA F DHG E. Consider these as four notes: E, F, D, E. In other words, consider it by omitting the notes in beats 2-3 of measures 1 and 3.  

Try playing just these four notes, E F D E, on the piano. You may consider F to be louder than E, or softer than E. When considering D and E, if you think of E as softer than D, then when considering measures 1-4 as a whole, the final E is the last note of the phrase, so it is preferable for it to be soft.  

The subsequent choice is whether to play the second F softer or louder. If playing it softer, consider E-F and D-E as two phrases, making the second note of each softer, and making D-E softer than E-F.  

Conversely, when considering the four notes E F D E as a single unit, consider F to be louder than E, then D to be slightly softer, and the final E to be even softer. In other words, the first E and the last E are soft, F is loud, and D is slightly softer than F. If the author were to play it, it would be the latter approach.  

Even just this small detail can make it sound completely different. Be very careful not to let these four measures sound flat.  

For measures 5-8, do not divide them into two parts; consider the entire four measures as a single unit. When measures 5-8 conclude, it's like a "period" in a sentence, so one tends to apply a crescendo, which is fine, but there are also notes that should not be played loudly. The G# in the right hand on beat 1 of measure 6 is a note arrived at by descending from C, B, A in the previous measure, so this note should be soft. Subsequently, for measures 7-8, the right hand, D C B A B A, should simply be thought of as D C B A, and gradually softened from D onwards. Especially, almost no force should be applied to the final A.  

For the middle section, measures 9-16, refer to measures 1-8. However, since measures 9-16 are in C major, please change the tone slightly. While measures 1-8 have high tension, measures 9-16 are a warm and gentle section.