Learn Turkish: Akşam kahve içmiyorum, böylece daha iyi uyuyorum. - I do not drink coffee in the evening; this way I sleep better.

Böylece means "in this way", "thus", or "so." It connects two clauses by showing that the second clause is a direct, positive result or consequence of the first clause.

Could I use a contrastive conjunction like bununla birlikte here instead of böylece?

No. Bununla birlikte means "however" or "nevertheless". If you used it here, the sentence would mean "I don't drink coffee in the evening; nevertheless, I sleep better." This illogically implies that avoiding coffee usually gives you a bad night's sleep! Because the second part is a logical result rather than a contrast, you need böylece.

How is the word böylece formed?

It comes from the word böyle (like this / such) combined with the suffix -ce, which often turns words into adverbs of manner. Literally, it translates to "in this manner" or "like this."

Why does the sentence use the present continuous tense (içmiyorum, uyuyorum) for a general habit instead of the aorist/simple present?

In conversational Turkish, the present continuous (-iyor) is extremely common for expressing current routines and daily habits. Using the aorist (içmem, uyurum) would also be correct, but it sounds a bit more formal or like a strict, lifelong personal rule.