Why can't I play minecraft multiplayer?

I'm kind of new at minecraft multiplayer and everytime I try to play with my sister it says can't connect to server. We have tried making a new server and opening to Lan. Any ideas?

Guest

Make sure you are both on the same internet and the same version of Minecraft.
Make sure you have 2 Minecraft accounts.
Make sure you open LAN in singleplayer.
Make sure you open main router ports if you choose too invite someone outside the house.

Rulep