People appreciate hospitality. That means if you are nice to the other players, give food to those suffering from starvation, attempt to help other players in danger (for instance, though you may not be able to save someone from drowning, if they call to you for help, go over and do your best to help.) One time, I built a house for a person, because it would reflect God’s love. I didn’t get to place a tract or anything, but if I end up back on that server, I hope they will come to me and ask me why I did what I did. Then I can share the message with them.
Books (if available) are extremely handy tools to convey information, especially when used as tracts. For instance, on one particular sever, I had gained the status of a ‘librarian’. Really what that was was just that most players knew I liked books, so it wasn’t a surprise when books (all Christian) started appearing in my house. (Now I had opened my mansion-like home to other players so they could live there if they wanted to.) Some thought perhaps they would like to read a book, so they read a tract without necessarily knowing that was the sort of book they had just started to read. I don’t know whether anyone became a believer from those books, but it at least planted some seeds.
Be social. Don’t just hide in a corner and do your own thing. Get out and make use of every single opportunity you can to get out with other people. Seize every single opportunity that presents itself and tell the good news. No second thoughts.
Earn the players’ trust. If they don’t trust you, there is a slim chance they will listen to you.