I januar plejer jeg at lave en ny plan for året.

This is because Danish main clauses follow the V2 rule: the finite verb usually comes in the second position.

So in:

I januar plejer jeg at lave en ny plan for året.

the first element is I januar, and the finite verb plejer must come next. After that comes the subject jeg.

Compare:

• Jeg plejer at lave en ny plan for året i januar.
• I januar plejer jeg at lave en ny plan for året.

Both are correct, but the second version emphasizes In January.

Plejer means usually, tend to, or am in the habit of.

So:

• Jeg plejer at lave ... = I usually make ...
• Jeg plejer at ... = I tend to ...

It describes a regular habit, not something happening right now.

After plejer, Danish normally uses at + infinitive.

So:

• plejer at lave
• plejer at læse
• plejer at gå

This is similar to English to in phrases like I tend to make or I usually like to make, although the exact grammar is not identical.

Lave often means make or do, but in many everyday contexts it is the natural verb for creating or putting together something.

So lave en plan means:

• make a plan
• draw up a plan
• come up with a plan

Even though English might sometimes say create a plan, Danish very naturally uses lave here.

Because plan is a common gender noun in Danish, so the indefinite article is en.

• en plan = a plan
• planen = the plan

Here the meaning is indefinite: a new plan, not the new plan.

So:

• en ny plan = a new plan
• den nye plan = the new plan

Because året means the year.

In Danish, this phrase is idiomatic:

• en plan for året = a plan for the year

Using år without the definite ending would sound incomplete here. Danish often uses the definite form where English may or may not use the.

In context, året usually means the year ahead or the current year, depending on the situation.

Yes. I is the normal preposition used with months in Danish.

• i januar = in January
• i februar = in February
• i marts = in March

So this works much like English in with months.

Yes. Plejer is present tense, but it expresses a habit.

So the sentence is grammatically present tense, but the meaning is something like:

• In January, I usually make a new plan for the year.
• In January, I tend to make a new plan for the year.

This is very common in Danish: the present tense is often used for repeated actions and habits.

Yes, absolutely.

That version is also correct:

• Jeg plejer at lave en ny plan for året i januar.

The difference is mostly one of emphasis and style:

• I januar plejer jeg ... puts focus on In January
• Jeg plejer ... i januar sounds a bit more neutral

Both mean essentially the same thing.

It usually means for the year ahead or for that year as a whole, depending on context.

So en ny plan for året can suggest:

• a plan covering the coming year
• a plan for the current year
• a yearly plan

The exact nuance depends on the situation, but the general idea is a plan connected to the year as a whole.

A very literal breakdown would be:

• I januar = In January
• plejer = usually / tend
• jeg = I
• at lave = to make
• en ny plan = a new plan
• for året = for the year

So the structure is roughly:

In January usually I to make a new plan for the year

That is not natural English, of course, but it helps show how the Danish sentence is built.