HI,
I have been trying to get into a group( any group! ) to do any mythic dungeon. Everytime I sign up for a group, i get declined or the group doesnt go clear through to the actual dungeon. I guess I am not doing it right.
any suggestions?
thanks
As a DPS you’re competing with far more people for a spot in any dungeon you apply for. If you apply, and another Hunter (or any DPS class) who is 20 item levels higher than you applies, it makes the most sense (usually) for the Party Leader to invite the better geared person.
It also doesn’t help that once you get invited that some party leaders might immediately kick you if they inspect your gear and see an Intellect trinket on a Hunter. It does nothing for you.
Best bet is to start your own group, as will be the advice of most people here. Making the group ensures you’re always invited. 
If you are a new player. WoW requires a lot of research and preparation before being desirable for groups. The best thing you can do is read your class and spec guide on wowhead or icyveins. Learn your rotation, priority stats and find the right gear and enchants.
Remember many players have been playing this game for over a decade and expect a lot from you without saying.
Add me: Taedas#1174
I’ll run a key or two with you.