Je genauer ich die Wörter in die Spalte schreibe, umso leichter kann ich sie später auswendig lernen.

It means the more ..., the more ... or the ..., the ... in English.

So here:

• Je genauer ... = The more accurately ...
• umso leichter ... = the more easily ...

This is a very common German comparison pattern:

• je + comparative, umso/desto + comparative

You will also often see desto instead of umso.

Because the je clause behaves like a subordinate clause.

In German subordinate clauses, the finite verb usually goes to the end:

• Je genauer ich die Wörter in die Spalte schreibe

The basic idea is:

• ich schreibe die Wörter ...
• but after je genauer, it becomes
• je genauer ich die Wörter ... schreibe

By contrast, the second part is a main clause, so its finite verb stays in the normal second position pattern:

• umso leichter kann ich sie später auswendig lernen

Because the sentence is comparing two degrees:

• the more accurately I write them
• the more easily I can memorize them

So German uses comparatives:

• genau → genauer
• leicht → leichter

Here both words are being used adverbially, because they describe how something is done:

• genauer describes schreibe
• leichter describes auswendig lernen

That is why there are no adjective endings here.

Compare:

• ein genauerer Eintrag = an adjective before a noun
• ich schreibe genauer = adverbial use, no ending

Because in is a two-way preposition.

• accusative: movement or direction into something
• dative: location inside something

Here the idea is writing the words into the column, so German uses accusative:

• in die Spalte

If you were only describing where something already is, you would use dative:

• Die Wörter stehen in der Spalte.

Also, Spalte is feminine:

• nominative: die Spalte
• accusative: die Spalte
• dative: der Spalte

die Wörter is the direct object of schreibe, so it is in the accusative plural.

For plural nouns, the article is die in both nominative and accusative, so the form does not change:

• nominative plural: die Wörter
• accusative plural: die Wörter

Later, sie refers back to die Wörter:

• umso leichter kann ich sie später auswendig lernen

So sie here means them, not she.

In a German main clause, the finite verb must be in second position.

Here the first position is taken by umso leichter, so the verb kann must come next:

1. umso leichter
2. kann
3. ich
4. sie
5. später
6. auswendig lernen

So the structure is perfectly normal for German.

A useful way to see it is:

• first slot: umso leichter
• second slot: kann
• then the rest of the clause follows

Because kann is the finite verb, and in a German main clause the finite verb must be in position 2.

Since umso leichter is already in position 1, kann has to come next. That pushes the subject ich after the verb:

• umso leichter kann ich ...

This is normal German word order and does not mean that ich is less important.

auswendig lernen means to learn by heart, to memorize, or to learn from memory.

It is best to treat it as a fixed expression:

• Ich lerne die Wörter auswendig.
• Ich kann die Wörter auswendig lernen.

In your sentence, it stays together at the end because of the modal verb kann:

• kann ich sie später auswendig lernen

So the sentence is not saying that I am already memorizing them, but that I can memorize them more easily later.

Yes. Both are standard and very common.

So this would also be correct:

• Je genauer ich die Wörter in die Spalte schreibe, desto leichter kann ich sie später auswendig lernen.

There is no important meaning difference here. It is mostly a matter of style or personal preference.

Because German object pronouns often come quite early in the clause, usually before many adverbs.

So this order is natural:

• kann ich sie später auswendig lernen

Here:

• sie = object pronoun
• später = time adverb

German often prefers:

• subject
• pronoun object
• adverb
• infinitive parts at the end

That is why sie später sounds natural here.

später means later.

It adds a time idea:

• I write the words now
• I memorize them later

So the sentence is connecting two stages:

1. writing the words carefully into the column
2. learning them by heart later

Without später, the sentence would still be grammatical, but it would lose that clear time contrast.

die Spalte usually means column, especially in things like:

• a table
• a worksheet
• notes laid out in columns
• a spreadsheet

So in die Spalte schreiben suggests writing the words into a specific column or section, not just writing them anywhere.

That helps explain why the sentence uses in die Spalte rather than something more general like aufs Papier or in mein Heft.