If you're a first-timer, research destinations that are well-travelled and get recommendations from other solo travellers. Once you've been to a couple of places on your own you'll have more confidence to visit more places which are off-the-beaten-track.
You're a one-man-band so make sure you pack efficiently - try microfibre travel towels, light-weight rucksack/suitcase and jacket, and a small carry-on. If you're a bookworm, don't pack tons of books - there'll be book swaps in cafes and hostels along the way!
Sociable hostels (check the reviews), organised group tours, volunteer placements and local day-trips are easy ways of mixing with other travellers (and you might even find a travel buddy or two).
Try not to arrive in the evening or late at night, especially if you're a first-timer. Trying to negotiate your way to a hostel in the dark when you're in an unfamiliar place can be quite overwhelming.
There are hundreds of apps out there, but the main ones are Skype, Maps.me (offline map) a translator app as well as a currency converter, Uber and Spotify for those long and boring coach rides.
Whether it's a local cooking class, a home-stay, a village visit or another local experience... get amongst it. You'll get a real feel for the culture and you'll meet other travellers with the same interests as you.