Choose a nearby destination with straightforward entry for your first trip, with direct flights where possible.
Book accommodation in a central location near transport; it saves more time and money than you expect.
Download offline city maps and transport apps before you go, and set up a suitable data plan.
Carry a bank card that works internationally and a little local cash, and inform your bank of your travel if needed.
Learn a few phrases in the local language; it opens doors and shows respect.
And do not fill every hour of your schedule; leave free time for spontaneous discoveries.