Learn Turkish: Yarın tatile gidiyoruz, eşyaları hazırlıyorum. - We are going on holiday tomorrow, I am preparing the things.

Just like in English, Turkish often uses the present continuous tense (-iyor) for planned future events. You could also use the future tense gideceğiz (we will go), but gidiyoruz sounds very natural for a set plan.

The translation says preparing the things. Could I use her şeyi here instead of eşyaları?

Eşya specifically means physical items, belongings, or luggage, which is perfect for packing. If you used her şeyi hazırlıyorum, it would mean I am preparing everything, which could include abstract things like plans or tickets, not just physical luggage.

Why does eşyalar (things) have an -ı at the end to make eşyaları?

That -ı is the specific direct object ending (the accusative case). Because you are preparing the specific things for your holiday, not just packing generic unknown items, we add -ı to eşyalar.

The root of the verb is hazırlamak (to prepare). Why is it spelled hazırlıyorum instead of hazırlayorum?