Learn Hardcore Japanese: kanozyo ha kasyu no you ni zyouzu ni utaimasu.

は marks 彼女 as the topic of the sentence: as for her / speaking of her.
You could say 彼女が歌手のように上手に歌います, but that would sound more like you are emphasizing she (as opposed to someone else) as the one who sings so well.
With 彼女は, you are just setting 彼女 as the topic and giving information about her singing ability in general, which is the most neutral and common choice here.

What does の do in 歌手のように?

の is linking 歌手 (a noun) to よう (also a noun) in the pattern:

Noun ＋の＋ように

This pattern means like (a) Noun / as if (a) Noun.
So 歌手のように literally means in a way that is like a singer.
Without の, 歌手ように would be ungrammatical.

What exactly does ように mean here, and how is it used?

よう means something like manner / way / appearance, and ～ように often translates as like / as if / in such a way that.
Here you have the structure:

Noun ＋のように＋ Verb

This describes how the action is performed.
So 歌手のように歌います means she sings in the way that a singer does → she sings like a singer.

Why are there two に in this sentence (ように and 上手に)? Are they the same?

They look the same, but they play slightly different roles:

ように – the に here turns よう into an adverbial expression that modifies the verb:
- 歌手のように歌います → sings like a singer (manner of singing).
上手に – this に is the adverbial form of the な‑adjective 上手(な):
- 上手な (good, skillful) → 上手に (well, skillfully).

Both に’s are creating adverbial phrases that describe how she sings, but one comes from よう, the other from a な‑adjective.

Why is it 上手に and not 上手 or 上手な?

上手 is a な‑adjective.

When you describe a noun, you use 上手な:
- 上手な歌 – a good song / skillful singing
When you describe a verb (an action), you usually turn it into an adverb with に:
- 上手に歌います – sings well / sings skillfully.

So here, since 歌います is a verb, 上手に is the natural form.
上手歌います or 上手な歌います are incorrect.

Could I change the word order, like 彼女は上手に歌手のように歌います?

Japanese word order is somewhat flexible, but not everything sounds natural.
The most natural patterns here are:

彼女は歌手のように上手に歌います。
彼女は上手に歌手のように歌います。 (possible, but a bit less smooth)

Both adverbial phrases (歌手のように, 上手に) modify 歌います, so they can switch places, but the original 歌手のように上手に歌います flows more naturally and is what you will usually hear.

What tense and politeness level is 歌います?

歌います is the polite non‑past form of 歌う.

Non‑past in Japanese covers both present and future, so it can mean:
- She sings (generally).
- She will sing.

The ます ending makes it polite (丁寧語).
The plain, casual form would be 歌う: 彼女は歌手のように上手に歌う。

Can I use みたいに instead of ように? What is the difference between 歌手みたいに and 歌手のように?

Yes, you can say:

彼女は歌手みたいに上手に歌います。

The meaning is very close: She sings well, like a singer.

Differences in nuance:

～のように
- More formal / standard.
- Feels slightly more written or careful speech.
～みたいに
- More casual / conversational.
- Very common in everyday speech.

So 歌手のみたいに is wrong, but 歌手みたいに (casual) and 歌手のように (neutral/formal) are both fine.

Could I leave out 彼女 or は? For example, just 歌手のように上手に歌います。

Yes. Japanese often omits subjects and even topics when they are clear from context.

歌手のように上手に歌います。
If the listener already knows who you are talking about, this is natural and would be understood as (She/He) sings well, like a singer.

Leaving out は but keeping 彼女 → 彼女、歌手のように上手に歌います
This can work in spoken, informal Japanese, but it sounds more like a fragment or a slightly emphatic style. The standard, neutral sentence is with は.

Is there a difference between saying 彼女は歌が上手です and 彼女は歌手のように上手に歌います?

Yes, there is a nuance difference.

彼女は歌が上手です。
- Literally: As for her, singing is good.
- Natural English: She is good at singing.
- A general statement about her ability.
彼女は歌手のように上手に歌います。
- Stresses how she sings: She sings well, like a singer.
- Adds a stronger, more vivid compliment by comparing her to a professional singer.

So the second sentence is more expressive and paints a more specific picture of how good she is.

Does 歌手のように mean she actually is a singer, or just that she sings as if she were one?

歌手のように itself does not say whether she is really a singer.
It only states that her manner / quality of singing is like that of a singer.

If she is not a singer, this is a compliment: She sings as well as a singer.
If she is a singer, it can sound a bit redundant, but it could still be used to emphasize how professional she sounds.

Context or additional sentences are needed to know whether she is actually a singer.

Could I say 彼女は歌手のように上手です instead of 上手に歌います?

You can say 彼女は歌手のように上手です, but the nuance is slightly different:

彼女は歌手のように上手に歌います。
- Directly describes the action: She sings well, like a singer.
彼女は歌手のように上手です。
- Describes her skill level more generally: She is as good (at it) as a singer.
- The verb 歌います is omitted and understood from context (usually singing, if that’s the topic).

Both are grammatical, but the original sentence is more explicit about the act of singing.