You could always join a casual free company. There are tons of them that don't mind people who can't log in all the time and if you are always busy it's better to have a group of people you can pull from when duty finder is being stingy. My FC is literally just friends and friends-of-friends doing their own thing and gathering together whenever any dungeon or boss fight needs to be done.

Free Company doesn't mean a hardcore raiding guild, all it is is a group of people that get bonuses for being in said group.