It pretty much the same as fighting a rathian or rathalos, as it shares both it's move sets. Upper battleaxe is a good weapon and I have used that many times against it though.
What I do usually do against the Yian Garuga though, is I take a light bowgun with me and plenty of explosive shots. If you take sml bone husk and wyvern claw, you can combine them to make clust lvl 2, which in total can give you about 50 explosive shots. That's a lot, and providing you have a powerful enough bowgun it should finish it off in one quest.