Sutra ću otići u grad.

Ću otići is the future tense: I will go / I will leave and go.

In Serbian, the future is often made with:

• a short form of hteti (ću, ćeš, će, ćemo, ćete, će)
• plus the infinitive of the main verb

So:

• ću = I will
• otići = to go away / to leave / to go

Together:

• ću otići = I will go

This is normal Serbian structure, even though in English we usually use just one helper word: will go.

This is about aspect, which is very important in Serbian.

• ići = to go (imperfective)
• otići = to leave / to go away / to go off (perfective)

In this sentence, otići suggests a single completed action in the future: tomorrow, the speaker will go to town/city.

A learner-friendly way to think about it:

• ići focuses more on the process, repetition, or general going
• otići focuses more on one completed departure

So:

• Sutra ću ići u grad. = Tomorrow I’ll be going to town / I’ll go to town.
• Sutra ću otići u grad. = Tomorrow I’ll go to town / Tomorrow I’ll head into town.

Both can be possible, but otići sounds more like a definite, completed trip.

Because ću is a clitic, and Serbian clitics usually go in the second position of the sentence or clause.

Here:

• Sutra = first element
• ću = clitic, so it comes next
• otići u grad = the rest

That gives:

• Sutra ću otići u grad.

This is very natural Serbian word order.

You can also move things around for emphasis, for example:

• Otići ću sutra u grad.
• U grad ću otići sutra.

But in all of these, ću still tries to stay in the second position.

Yes. That is grammatically correct.

Serbian word order is more flexible than English word order. Different orders can sound slightly different in emphasis, but they can all be correct.

Compare:

• Sutra ću otići u grad. = neutral; emphasizes tomorrow first
• Otići ću u grad sutra. = emphasizes the action a bit more
• U grad ću otići sutra. = emphasizes the destination

A learner should know that Serbian often changes word order for focus rather than basic grammar.

Because Serbian usually does not need the subject pronoun when it is already clear from the verb form.

• ću already tells us the subject is I
• so ja is unnecessary

You could say:

• Ja ću otići u grad.

But that adds emphasis, something like:

• I will go to town
• I am the one who will go

So the version without ja is more neutral and common.

U grad literally means into the city/town.

In everyday English translation, it often becomes:

• to town
• to the city

The exact English wording depends on context.

In Serbian:

• grad can mean city
• but in many situations it also means the town / downtown / the urban center, especially from the speaker’s point of view

So idem u grad is a very common expression meaning something like:

• I’m going into town
• I’m going to the city center

Because after u, Serbian can use different cases depending on meaning.

With movement toward a place, Serbian uses the accusative:

• u grad = into town / to town

With location in a place, Serbian uses the locative:

• u gradu = in the city

So:

• Sutra ću otići u grad. = Tomorrow I’ll go to town.
• Sutra ću biti u gradu. = Tomorrow I’ll be in the city.

This is a very important pattern:

• u + accusative = motion/direction
• u + locative = location

It can mean both, depending on context.

In dictionaries, grad is often given as city, but in real life it can also function like:

• town
• downtown
• the center
• the main urban area

That is why u grad is often best translated naturally, not mechanically. In many contexts, Tomorrow I’m going into town sounds more natural than Tomorrow I will go into the city.

It is neutral and natural in both speech and writing.

Nothing in Sutra ću otići u grad. is especially formal or especially slangy. It is a standard Serbian sentence.

If anything, it sounds like a normal everyday statement.

A simple pronunciation guide is:

• otići ≈ oh-TEE-chee

More specifically:

• o as in a short o
• ti with stress on that syllable
• ć is a soft sound, somewhat like a softer ch
• ći sounds roughly like chee, but softer than English ch

Also:

• ću is pronounced roughly like choo, but again with a softer ć

So:

• Sutra ću otići u grad might sound roughly like
  SOO-tra choo oh-TEE-chee oo grahd

That is only an approximation, but it can help a beginner.

Yes, slightly.

Because the verb is otići, it can carry the sense of:

• go away
• leave
• head off

In many contexts, though, the most natural English translation is still just:

• Tomorrow I’ll go to town.

But the Serbian verb has a bit more of a departure/completion feeling than plain ići.

Yes. Sutra is flexible.

You can say:

• Sutra ću otići u grad.
• Otići ću sutra u grad.
• Otići ću u grad sutra.
• U grad ću otići sutra.

All of these are possible. The differences are mainly about emphasis and rhythm, not basic meaning.

The version with Sutra first is very common because it sets the time right away:

• Tomorrow, I’ll go to town.

Yes, but depending on context they might also say:

• Sutra idem u grad. = Tomorrow I’m going to town.
• Sutra ću ići u grad. = Tomorrow I’ll go to town.
• Sutra ću otići u grad. = Tomorrow I’ll go to town / head into town.

In casual speech, Sutra idem u grad is extremely common and often sounds very natural for a planned future action, even though it is grammatically present tense.

So your sentence is correct and natural, but it is not the only everyday way to express the idea.