This is the real warning here. Play alone and you have to rely on people you don't know, setting yourself up to get scammed.
My advice is to go to a Linkshell Concierge, Northern San d'Oria (K-9), Bastok Mines (K-9), Windurst Walls (C-13), and pick up a linkshell pearl that roughly fits you. Greet everyone politely, ask if and when they do the content you are trying to complete. If there is enough overlap, ask them if you could join that event.
When there are people with whom you mesh well with, create your own subgroups for Ambu, Sortie, Omen, Oddy or whatever else is still on your to do list.