Pogledaj tu etiketu; na njoj piše da limenka rajčica nije skupa.

Pogledaj is the imperative of the perfective verb pogledati, so it means take a look or look as a single, completed action.

By contrast, gledaj comes from the imperfective gledati and usually means keep looking, watch, or be looking.

So in this sentence, Pogledaj tu etiketu sounds natural because the speaker wants one quick action: look at that label.

Tu is the feminine accusative singular form of taj.

It agrees with etiketu, so together tu etiketu means something like that label. In real usage, taj/tu/to can sometimes feel a bit broader than English that, and depending on context it may point to something already visible, already known, or just being singled out.

So the important thing here is:

• taj = demonstrative word like that
• tu = the form used with a feminine singular noun in the accusative
• etiketu is feminine singular accusative, so tu matches it

Because etiketa is the direct object of pogledaj, and that requires the accusative case.

For many feminine nouns ending in -a, the singular accusative ends in -u:

• etiketa → etiketu
• knjiga → knjigu
• torba → torbu

So:

• etiketa = nominative, dictionary form
• etiketu = accusative, used after pogledaj

Croatian has no articles, so there is no direct equivalent of English a or the.

That means limenka rajčica can mean:

• a can of tomatoes
• the can of tomatoes

The exact meaning depends on context. English must choose an article, but Croatian usually does not mark that difference explicitly.

Here, the surrounding context tells you what is meant.

Literally, it is something like on it writes or more naturally on it, it is written.

In Croatian, piše is very often used in this kind of impersonal way to mean it says or it is written:

• Na vratima piše... = It says on the door...
• Na kutiji piše... = It says on the box...

So na njoj piše da... means it says on it that...

Also, njoj refers back to etiketa. Croatian uses gendered pronouns for things as well as people, because nouns have grammatical gender:

• etiketa is feminine
• so the pronoun referring to it is also feminine

Because na can take different cases depending on meaning.

Here it describes location, not movement:

• na njoj = on it → locative
• na nju = onto it / onto her → accusative, usually movement toward a surface

So:

• Piše na njoj = something is written on it
• Stavi to na nju = put that onto it

In this sentence, the meaning is static location, so na njoj is correct.

Da introduces the content of what is written. Here it works like English that:

• piše da... = it says that...

So the structure is:

• na njoj piše = it says on it
• da limenka rajčica nije skupa = that the can of tomatoes is not expensive

Croatian uses da very often to introduce subordinate clauses like this.

After a container or quantity word like limenka (can), Croatian often uses the genitive for what the container contains.

So:

• limenka rajčica = a can of tomatoes
• compare:
  • boca vina = a bottle of wine
  • kutija keksa = a box of biscuits
  • vrećica bombona = a bag of sweets

Here rajčica is genitive plural, meaning of tomatoes.

What makes it confusing is that the genitive plural form rajčica looks the same as the nominative singular form rajčica. So although it looks like tomato, in this phrase it actually means tomatoes in the genitive plural.

Because the adjective agrees with limenka, which is feminine singular.

So:

• limenka is feminine
• therefore the adjective is feminine too: skupa

Compare:

• sok nije skup = the juice is not expensive
• voda nije skupa = the water is not expensive
• jelo nije skupo = the meal is not expensive

So nije skupa means is not expensive, with the adjective matching limenka.

Because that is simply the standard negative form of biti in the present tense.

The present negative forms are:

• nisam
• nisi
• nije
• nismo
• niste
• nisu

So nije skupa means is not expensive.

Croatian word order is fairly flexible, but the version here is natural and clear.

• Pogledaj tu etiketu gives the command first.
• na njoj piše highlights where the information is written.
• da limenka rajčica nije skupa gives the content.

You could rearrange parts of the sentence, but the emphasis would change. For example, Piše na njoj da... is also possible, but it sounds slightly different in focus.

As for the semicolon, it links two closely related independent clauses:

• Pogledaj tu etiketu
• na njoj piše da...

A full stop would also be possible. The semicolon just shows a strong connection between the two parts.