Analysis should be more analytical than conversational in style. Although personal opinions will be expressed, make sure that you give plenty of details to back up the statements. Be certain that you include specifics about whether the student completed the objectives of the assignment. Use the phrase "I like...." sparingly. Here personal opinions are expressed too often:

I like the beat of your pitched instruments a lot.  I really liked your whole project.

Every specialty has terms that “insiders” understand and regularly use. One important aspect of learning a new discipline is to understand the vocabulary employed by experts in their field. Sometimes informal language uses the same vocabulary but in different ways. For instance:

I like the beat of your pitched instruments a lot. 

The word "beat" does not have the same meaning as "rhythm." I think the author is refering to the choice of notes in the pitched instruments but it is unclear. Also be aware that "beat" can be better expressed by the word "tempo."

The melody changes tempo with the quicker notes.

Non-musicians often confuse the word "tempo" with "rhythm." Tempo is the regular pacing of beats. Typically the tempo does not change in a composition, however, the speed of notes and the rhythms often change. Be sure you understand the difference.

Here is another example of a problem with a musical term:

I would also suggest mixing your pitched instruments and making sure the percussion and pitched instruments sound harmonic.

The word “harmonic” has special meanings in music beyond the informal definition. In musical applications percussion (non-pitched instruments) are considered non-harmonic, that is, they don’t produce tones that can be harmonized. Thus, percussion instruments don't sound harmonic.

Here is another example using musical terms inappropriately:

I thought this was an interesting piece since it was very upbeat which gave it a dynamic feel.

“Upbeat” has a specific meaning in music, but here the author is using it informally. I think the author is referring to the tempo of the work, and it would be better to reference the faster tempo than use the word “upbeat.” “Dynamic” or “dynamics” also has a special meaning in music. Try to use another term to describe the force or impulse of the music.

Careful of spelling:

The one thing that I think could be improved in this composition is the base line.

Bass not base!

Avoid ambiguous and informal language as much as possible:

This is a nice little arrangement featuring a soft lead melody.

The melody is pretty laid-back….

Use musical terms to describe what you are hearing. Is it the number of notes, the choice of instrument, or the choice of pitches? Some examples: “the melody is not complicated, generally a note per beat (quarter note per beat).” “The choice of the flute gives the melody a more lyrical quality than choosing a trumpet, for example.”

This comment was interesting, but needed to be more specific:

It was very relaxed and gave me a country, laid back type feel.

Was it the tempo, choice of instrumentation, or something else? For instance, “The slower tempo, quieter percussion parts, and the choice of acoustic guitars reminded me of the relaxed feel of country music.”

This comment also needed more explanation:

Rhythm and tempo was very smooth.

I am not sure what the author means by “smooth.” Are smoother tempos slower? Is a rhythm smoother by having less notes? There were similar issues with:

It sort of had a creepy eerie sort of tone to it.  It reminded me of an old video game that I used to play on Nintendo. 

Be more specific. Was it the instrumentation, tempo, bass line or melody that gave you that impression?

AND, don't forget to properly discuss instruments:

I like your choice of instruments as well, the shaker sound made it very interesting. 

Refer to the student report and find the correct instrument name: Cabasa. Give actual instrument names instead of descriptions: “twanging sounding instrument,” “plucking instrument,” or “tooting noise.”