Sada pišem urednije nego jučer.

Pišem is the 1st person singular present tense form of pisati (to write).

So:

• ja pišem = I write / I am writing

Croatian often uses the present tense where English might say either I write or I am writing, depending on context. Here, with sada (now), it naturally means I am writing now.

In Croatian, subject pronouns are often left out because the verb ending already shows who the subject is.

• pišem already means I write / I am writing
• so ja is not necessary

You could say Ja sada pišem urednije nego jučer, but adding ja usually gives extra emphasis, like I am writing more neatly now.

Here, urednije is an adverb in the comparative form.

It modifies the verb pišem, so it tells us how someone is writing:

• uredno = neatly
• urednije = more neatly

If it were an adjective, it would describe a noun. But in this sentence it describes the action of writing, so it is adverbial.

It comes from the adverb uredno (neatly / tidily).

The comparative is:

• uredno → urednije

So the pattern is:

• positive: uredno = neatly
• comparative: urednije = more neatly

In Croatian, many adverbs form the comparative with endings like -ije or -e, depending on the word.

Nego means than in comparisons.

So:

• urednije nego jučer = more neatly than yesterday

It is the normal word to use when comparing one action, quality, or state with another.

Examples:

• Viši je nego brat. = He is taller than his brother.
• Radim brže nego prije. = I work faster than before.

Jučer is an adverb meaning yesterday. As an adverb, it usually stays in this same form.

In this sentence, jučer works as the comparison point:

• nego jučer = than yesterday

There is no preposition because Croatian often uses time adverbs directly:

• danas = today
• sutra = tomorrow
• jučer = yesterday

Yes. Sada and sad both mean now.

• Sada is slightly fuller and sometimes feels a bit more neutral or careful.
• Sad is very common in everyday speech.

So these are both natural:

• Sada pišem urednije nego jučer.
• Sad pišem urednije nego jučer.

Yes, Croatian word order is fairly flexible.

The neutral order here is:

• Sada pišem urednije nego jučer.

But you could also hear:

• Pišem sada urednije nego jučer.
• Urednije pišem sada nego jučer.
• Jučer pišem urednije nego sada would change the meaning, so be careful

Changing word order often changes emphasis, not the basic grammar. The original sentence sounds natural and straightforward.

Because sada means now, and the speaker is describing what is happening at the present time.

Croatian present tense often covers both:

• I write
• I am writing

With sada, the meaning becomes clearly current:

• Sada pišem... = I’m writing now...

Yes, it matters. Pisati is an imperfective verb.

Imperfective verbs are used for:

• ongoing actions
• repeated actions
• general processes

That fits this sentence well, because the speaker is describing the way the action is happening now.

Its perfective partner is usually napisati, which means something more like to write down / to write and finish. A perfective verb would not sound right here if the focus is on the ongoing action and how neatly it is being done.

Yes, there could be. Croatian often leaves out an object if it is obvious or unimportant.

So pišem by itself can mean:

• I am writing
• with the object understood from context, like a letter, homework, notes, etc.

The sentence focuses on how the speaker is writing, not on what they are writing.

Its basic sense here is more neatly or more tidily. Depending on context, it can also suggest:

• more carefully
• in a more orderly way
• more legibly

So it is not only about physical neatness; it can also imply that the writing looks better organized or cleaner than before.

Normally, for this kind of comparison, nego is the expected word.

So:

• urednije nego jučer = correct and natural

Croatian sometimes uses other comparison structures in different contexts, but in this sentence nego is the standard choice.