siken no mae ha, dekiru dake hayaku neru you ni site imasu.

試験の前 means before the exam or before exams.

• 試験 = exam
• 前 = before, in front of
• の links the two nouns, so 試験の前 literally means the before of the exam
• は marks that whole time expression as the topic: as for before exams...

So 試験の前は sets the scene for the rest of the sentence: When it is before an exam, ...

In a sentence like this, it usually means the general period leading up to the exam, not just the last few minutes before it.

So it suggests something like:

• in the days before an exam
• when an exam is coming up
• before exams

That fits naturally with the rest of the sentence, because going to bed early is usually a habit or plan during that period.

できるだけ means as much as possible or as... as one can.

In this sentence, it modifies 早く:

• できるだけ早く = as early as possible

So the idea is not just early, but as early as I can manage.

You can use できるだけ with many other expressions too:

• できるだけ日本語で話します。 = I speak in Japanese as much as possible.
• できるだけ毎日勉強します。 = I study every day as much as possible / whenever I can.

早い is the plain i-adjective form, meaning early.

When an i-adjective modifies a verb, you usually change -い to -く:

• 早い = early
• 早く = early, in an adverbial way

Here, 早く modifies 寝る:

• 早く寝る = go to bed early / sleep early

So 早く is used because it describes how the action of sleeping happens.

The pattern here is:

dictionary form verb + ようにしている

This grammar means make an effort to do, try to do regularly, or make it a habit to do.

So:

• 寝るようにしている = I try to sleep / I make a habit of sleeping

The dictionary form is normal in this pattern when the meaning is positive:

• 野菜を食べるようにしています。 = I try to eat vegetables.
• 毎日歩くようにしています。 = I try to walk every day.

For negative habits, you often see:

• 食べすぎないようにしています。 = I try not to overeat.

No, it is softer and more nuanced than 寝ます.

• 寝ます = I sleep / I go to bed
• 寝るようにしています = I try to go to bed / I make a point of going to bed / I make it a habit to go to bed

This grammar shows effort, intention, or a repeated habit, not just a simple fact.

So the sentence does not merely say I go to bed early before exams. It suggests:

• I try to do that
• I make a conscious effort to do that
• it is my usual practice

〜ようにしている often describes an ongoing habit or continuing effort.

• 〜ようにする can sound more like I will try to... or I make it a point to...
• 〜ようにしている emphasizes that this is something the speaker is currently keeping up as a habit

So:

• 早く寝るようにする = I will try to go to bed early / I make a point of going to bed early
• 早く寝るようにしている = I am trying to go to bed early / I usually make a point of going to bed early

In this sentence, しています works well because it describes a recurring practice before exams.

In natural English, go to bed early is usually the best translation.

Japanese 寝る literally means sleep, but in many everyday contexts it can refer to going to bed. So:

• 早く寝る = go to bed early

That is the most natural understanding here.

The subject is not stated explicitly, which is very normal in Japanese.

From context, the speaker usually means I:

• As for before exams, I try to go to bed as early as possible.

Japanese often leaves out subjects when they are clear from context. So even though there is no visible 私 in the sentence, the meaning is still natural and complete.

は is used because the phrase is being presented as the topic: as for before exams...

A time expression does not always need に, especially with relative time words like:

• 今日 = today
• 明日 = tomorrow
• 昨日 = yesterday
• 試験の前 = before the exam

If you used に, the nuance would be different, and in this sentence は is more natural because the speaker is talking about what they do during that situation/time frame.

So 試験の前は means something like:

• when it is before an exam
• as for the period before exams

No, できる早く is not natural here.

The set expression is できるだけ, meaning as much as possible. It works as a fixed phrase.

So you say:

• できるだけ早く = as early as possible

Not:

• できる早く

This is an expression worth memorizing as a chunk.

The sentence does not sound like a hard rule or a dramatic statement. It sounds calm and habitual.

A natural nuance is:

• Before exams, I try to go to bed as early as possible.
• When I have an exam coming up, I make a point of going to bed early.

So the speaker is describing a personal habit or self-care strategy, not just a one-time action.