You can find all the previous games on the game page, when you click on the number of played games. You can scroll then through the list and see who won the solo games, e.g. the last won solo game is this one:
https://boardgamearena.com/table?table=929618371
I played solo during alpha, mainly to test specific things. As this is not representative, I won't link one of these games. However my thoughts about it:
1. The best equipment is perimeter security device, as you can discover rooms without cautious movement and the risk of getting attacked. Bajonet with engineer might also work, but it's not as good.
2. Avoid combat as best as you can. Intruders next to you in a corridor, you don't want to cross? Ignore them! Exception: If you want to escape, then try to clear that corridor, if you have time and resources.
3. Bring enough oxygen. I'd say at least 2, better 3. You don't have time to enable all life support and nobody else will do it for you.
4. Character selection: I'd like to pick either consultant, engineer or medic (in this order). I think the worst character for solo is officer.
5. Luck: Some things, you cannot influence, but will influence your chances: the mission, the robot, dice rolls/card draws.