Sem ter feito um rascunho, é mais fácil esquecer uma vírgula ou um ponto final.

Sem ter feito uses the compound infinitive, which means without having done.

So:

• sem fazer um rascunho = without making a draft / without doing a draft
• sem ter feito um rascunho = without having made a draft

In this sentence, sem ter feito emphasizes that the draft was not completed beforehand, before the forgetting happens. It points to an action that should already have happened earlier.

This is very natural in Portuguese when one action is clearly earlier than another:

• Sem ter estudado, é difícil passar.
• Sem ter lido o texto, não posso comentar.

So sem ter feito is more precise here than sem fazer.

Ter feito is the compound infinitive:

• ter = infinitive of to have
• feito = past participle of fazer (done / made)

Together, ter feito means to have done / to have made.

Examples:

• Depois de ter comido = after having eaten
• Por ter chegado tarde = for having arrived late
• Sem ter feito um rascunho = without having made a draft

English learners often compare it to having done, but in Portuguese the form literally uses to have done.

Because fazer is irregular.

Its past participle is:

• feito = done / made

Not:

• fazido ❌

Some important irregular past participles in Portuguese are:

• fazer → feito
• dizer → dito
• escrever → escrito
• ver → visto
• abrir → aberto

So ter feito is the correct form.

The sentence is built around the expression:

• é mais fácil + infinitive = it is easier to...

So:

• é mais fácil esquecer... = it is easier to forget...

The first part, Sem ter feito um rascunho, gives the condition:

• Without having made a draft, it is easier to forget...

Portuguese often uses é + adjective + infinitive in the same way English uses it is + adjective + infinitive:

• É difícil entender isto. = It is difficult to understand this.
• É importante estudar. = It is important to study.

Mais fácil means easier, the comparative form of fácil.

So:

• fácil = easy
• mais fácil = easier

The sentence is saying that when you have not made a draft, forgetting punctuation becomes easier / more likely.

Portuguese often uses mais + adjective to form the comparative:

• mais difícil = more difficult
• mais rápido = faster
• mais fácil = easier

Because it follows é mais fácil.

The pattern is:

• é fácil + infinitive
• é difícil + infinitive
• é mais fácil + infinitive

So:

• É fácil aprender.
• É difícil responder.
• É mais fácil esquecer uma vírgula...

This works just like English:

• It is easy to learn
• It is difficult to answer
• It is easier to forget...

Because esquecer is normally a direct transitive verb in this meaning.

So you say:

• esquecer uma palavra = to forget a word
• esquecer o livro = to forget the book
• esquecer uma vírgula = to forget a comma

No preposition is needed.

English speakers sometimes expect something like forget about, but in Portuguese that is a different structure:

• esquecer-se de can also exist, especially in some contexts
• but here plain esquecer + object is the straightforward choice

So esquecer uma vírgula is perfectly normal.

Rascunho means draft, rough draft, or rough version.

It is something written before the final version, often to organize ideas and catch mistakes.

Examples:

• Fiz um rascunho da redação. = I made a draft of the essay.
• Escreve primeiro em rascunho. = Write it in draft form first.

In this sentence, the idea is that if you do not prepare a draft first, you are more likely to miss punctuation.

Because Portuguese nouns have grammatical gender.

• rascunho is masculine → um rascunho
• vírgula is feminine → uma vírgula
• ponto final is masculine → um ponto final

So the articles must match:

• um for masculine singular
• uma for feminine singular

This does not necessarily match natural gender, because these are objects, not people. It is just part of the noun’s grammar.

In European Portuguese, ponto final is the normal term for the punctuation mark .

In British English, that is full stop. In American English, it is period.

So:

• vírgula = comma
• ponto final = full stop / period

Literally, ponto final means final point, but in real usage it is simply the punctuation mark at the end of a sentence.

Ou means or.

So:

• uma vírgula ou um ponto final = a comma or a full stop

The sentence means that without a draft, you may forget one kind of punctuation or the other. It is not necessarily saying you forget both.

If it used e, it would suggest and:

• uma vírgula e um ponto final = a comma and a full stop

No essential word is missing.

Sem ter feito um rascunho is a complete prepositional phrase:

• sem = without
• ter feito = having done / having made
• um rascunho = a draft

Then the main clause begins:

• é mais fácil esquecer... = it is easier to forget...

Portuguese often leaves out an explicit subject when English uses it:

• É fácil. = It is easy.
• É verdade. = It is true.
• É mais fácil esquecer... = It is easier to forget...

So there is no missing article here; it is just a normal Portuguese sentence structure.

Yes. A few natural alternatives are possible, though they may sound slightly different in emphasis.

For example:

• Sem fazer um rascunho, é mais fácil esquecer uma vírgula ou um ponto final.
  This is simpler and also natural, but it focuses less clearly on the idea of not having made the draft beforehand.

• Se não fizeres um rascunho, é mais fácil esqueceres-te de uma vírgula ou de um ponto final.
  This uses a more direct if you do not... structure.

• Sem um rascunho, é mais fácil esquecer uma vírgula ou um ponto final.
  This is shorter and less explicit.

The original sentence is a good formal, clear way to express the idea.

Yes, it is fully natural in European Portuguese.

A few features that fit well with standard written Portuguese are:

• the use of sem ter feito for without having done
• the impersonal structure é mais fácil + infinitive
• punctuation vocabulary like vírgula and ponto final

Nothing in the sentence sounds strange or unnatural for Portugal. It is the kind of sentence you could see in educational or explanatory writing.