At that level your best bet for fast advancing is one other person. The two
of you together can take yellow mobs, have no problems and still gain
quickly. I hunted with an equal level magician(my best friend in RL) from
about 6th-12th. From there we hooked up with some other friends and now I
have a full group that I hunt with constantly(we are all 16th now). I know
that you can group with 5 or 6 others and hunt but until you make 10th and
higher you really don't need the full group, just get one other person that
understands your style and the two of you will do fine.

As far as what to fight well you have a couple of options if you want to
stay on Faydwer. With a group you can enter Crushbone and take the
centurions there, just beware of Crush's train and move if you hear anyone
shouting about it. Solo, or with the one other person, you can stick to the
Orc Camp and kill the cents and oracles that spawn there(some will still be
white and yellow to you). Lesser Faydark is an option if you don't mind
killing pixies, the tower there is usually empty of other players and you
can still gain from the pranksters. If none of those options are appealing
then there is always Butcherblock. Head over there with your group and take
Dwarf Skel's(only spawn at night), Giant Bat's, Roaming Goblins and Spiders.
If you prefer to camp then there are numerous goblin camps dotting the
landscape although beware of the goblin wizards and shamans as they are
probably too tough for you at 7th.

Hope this helps.

Yours,

~Aereuss Ravins of Tarew Marr