I november försöker jag dricka mindre kaffe på kvällen.

With months in Swedish, you normally use i to mean in:

• i november = in November
• i januari = in January
• i sommar = in summer

So I november means in November or during November.

Swedish does not use an article here, so you do not say the equivalent of in the November.

In Swedish, names of months and days are normally written with a lowercase letter:

• november
• måndag
• fredag

This is different from English, where November and Monday are capitalized.

In your sentence, I is capitalized only because it is the first word of the sentence, not because the month name itself is capitalized.

This is because of the Swedish V2 rule: in a main clause, the finite verb usually comes in second position.

If the sentence begins with the subject, you get:

• Jag försöker dricka mindre kaffe.

But if something else comes first, such as a time expression, the verb still stays in second position, and the subject moves after it:

• I november försöker jag dricka mindre kaffe.

So:

• first element: I november
• second element: försöker
• then subject: jag

This kind of word order is very common in Swedish.

Försöker is the present tense of försöka (to try).

Swedish often uses the present tense for:

• things happening now
• repeated habits
• plans or intentions in a current time period

So I november försöker jag... means that during November, the speaker is making this effort or following this plan.

English often does something similar:

• In November I’m trying to drink less coffee...

After försöka (to try), the next verb is normally in the infinitive:

• försöker dricka = try to drink
• försöker sova = try to sleep
• försöker läsa = try to read

So dricka is there because it is the action the speaker is trying to do.

Both försöker dricka and försöker att dricka can occur, but leaving out att is very common and natural.

So this sentence is perfectly normal as it stands:

• I november försöker jag dricka mindre kaffe på kvällen.

Adding att would also be understandable:

• I november försöker jag att dricka mindre kaffe på kvällen.

But the version without att often sounds smoother and more idiomatic in everyday Swedish.

Use mindre for something uncountable, where you are talking about amount.

Kaffe here is a mass noun, like water or milk, so Swedish uses mindre:

• mindre kaffe = less coffee

Use färre for countable things:

• färre koppar kaffe = fewer cups of coffee
• färre böcker = fewer books

So:

• mindre kaffe = less coffee
• färre koppar kaffe = fewer cups of coffee

Because kaffe is being used in a general sense, as a substance:

• dricka kaffe = drink coffee
• köpa mjölk = buy milk
• äta ris = eat rice

Swedish often uses no article with mass nouns in this kind of general meaning.

If you add an article, the meaning changes:

• ett kaffe often means a coffee, for example one cup or one serving

So dricka mindre kaffe means drink less coffee in general, not drink fewer individual coffees.

In Swedish, på kvällen is a standard expression meaning in the evening or at night/evening time, depending on context.

Similar expressions are:

• på morgonen = in the morning
• på eftermiddagen = in the afternoon
• på kvällen = in the evening

So dricka mindre kaffe på kvällen means drink less coffee in the evening.

This is part of a common Swedish time expression pattern:

• på morgonen
• på förmiddagen
• på eftermiddagen
• på kvällen
• på natten

Even though the noun is definite in form, it does not always mean one specific evening. It is just how Swedish usually expresses these times of day after på.

So you should think of på kvällen as a set phrase meaning in the evening.

This is a very common question.

• i kväll = this evening / tonight
• på kvällen = in the evening, more generally

Examples:

• Jag jobbar i kväll. = I’m working tonight.
• Jag dricker sällan kaffe på kvällen. = I rarely drink coffee in the evening.

In your sentence, på kvällen is used because it describes a general habit or time of day, not just one specific evening.