Solo travel rewards confidence, and confidence is mostly a matter of preparation.
Share your itinerary with someone at home before you go quiet on the trail or in a country with patchy signal, and agree on a simple check-in schedule rather than promising to call every day. A rough plan someone else knows is worth more than a perfect one only you carry.
Book the first night's accommodation in a well-reviewed, central spot even if it costs a little more — arriving exhausted into an unfamiliar neighbourhood after dark is when good judgment slips. After that first night, trust your instincts about a street, a taxi or a person; hesitation is information, not rudeness.
Dress to blend in rather than stand out, keep a photocopy of your passport separate from the original, and learn to say 'no thank you, I'm meeting someone' in the local language — it ends most unwanted conversations faster than a real explanation ever does.