neru mae ni, genkan no kagi wo kakeru you ni site imasu.

With 前に, Japanese normally uses the dictionary form of a verb:

• 寝る前に = before sleeping / before I go to bed

The idea is that the action in 前に has not happened yet at that point, so the plain dictionary form is used.

Compare:

• 寝る前に = before sleeping
• 寝た後で = after sleeping

So 寝る前に is the standard pattern.

前に means before.

In this sentence, it connects two actions:

• 寝る前に = before going to bed
• 玄関の鍵をかける = lock the front door / entrance lock

So the whole structure is:

• A前に、B = Before A, B

Here:

• 寝る前に、玄関の鍵をかける
  = Before going to bed, I lock the front door.

Literally, 玄関の鍵 means the entrance’s key/lock.

A few important points:

• 玄関 = entranceway, front entrance, entry area
• 鍵 can mean key or lock, depending on context

Because the sentence says 鍵をかける, it does not mean use a key in a literal object sense. The expression 鍵をかける means to lock.

So in natural English, 玄関の鍵をかける usually becomes:

• lock the front door
• lock the entrance

Even though the Japanese wording is literally closer to put the lock on the entrance.

Because 鍵 is the direct object of かける in the expression 鍵をかける.

Japanese treats this as a set phrase:

• 鍵をかける = to lock

So を marks the thing being acted on.

Even though English says lock the door, Japanese often says 鍵をかける instead. That is just the natural Japanese expression.

Yes—かける is a very common verb with many meanings, such as:

• to hang
• to put on
• to make a phone call
• to spend time/money
• and more

Here, in the fixed expression 鍵をかける, it means:

• to lock

So you should learn 鍵をかける as one chunk.

Related expression:

• 鍵を開ける = to unlock

ようにしている means something like:

• make a point of doing
• try to do regularly
• make sure to do
• have a habit of doing

So this sentence is not just saying that the speaker locks the door one time. It suggests a habit or ongoing effort.

So:

• 鍵をかけるようにしています
  = I make sure to lock it = I try to remember to lock it = I’m in the habit of locking it

This pattern is very common for habits and intentional routines.

Because ようにしている describes an ongoing habit or practice.

Compare:

• 〜ようにする = I will try to do / I make it a point to do
• 〜ようにしている = I am making it a point to do / I habitually try to do

So しています shows that this is an existing routine, not just a one-time decision.

Also, しています is the polite form, which matches the overall polite tone of the sentence.

This is a very common question.

Both can describe habits, but the nuance is different:

• 〜ようにしている = I try to do this / I make an effort to do this
• 〜ことにしている = I have decided to do this / I have a personal rule to do this

So:

• 寝る前に、玄関の鍵をかけるようにしています
  = I make sure to lock the front door before bed.
• 寝る前に、玄関の鍵をかけることにしています
  = I have a rule that I lock the front door before bed.

In this sentence, ようにしています sounds slightly softer and more like a practical habit.

Japanese often omits the subject when it is clear from context.

Here, the sentence naturally implies:

• I make sure to lock the front door before bed.

So a full version could be:

• 私は寝る前に、玄関の鍵をかけるようにしています。

But in normal Japanese, 私は is often unnecessary and would usually be omitted unless the speaker wants emphasis or contrast.

No, it is not grammatically required.

The sentence can also be written as:

• 寝る前に玄関の鍵をかけるようにしています。

The comma just adds a small pause and can make the sentence easier to read.

So both are fine.

Yes. That is exactly the kind of nuance ようにしています can have.

It suggests:

• this is the speaker’s usual practice
• the speaker intentionally tries to do it
• it may not be a 100% perfect rule every single time

So it is a little softer than a hard, absolute statement like:

• 必ず鍵をかけます = I definitely always lock it.

Instead, ようにしています focuses on habit and effort.