Good CON gear and GM abilities R46+Follow

For a weapon, try to pick up a Jade Crook +1 (or +2/+3 if you can afford it). Eventually you will want the Astaroth Cane from the r45 dungeon.

For the body piece, go with a Vintage Robe until you can get the Revolutionary's Briauld from the r45 dungeon.

For the headpiece you can pick up a Vintage Jester's Cap or Harlequin Cap. Both have nearly identical stats, but the Vintage is easier to get now that they increased the drop rate on faction leve rewards. Used to sell for 3 mil in the wards, currently down to 260k on my server.

For gloves most Cons go with the Bowyer's Braces or Toadskin Mitts. The mitts have much better stats but no Con affinity.

For the waist you can pick up the Harlequin's Belt from the faction NM, though the stats are pretty much identical to the Tarred Leather Belt.

For pants you are looking at Vintage Hose until you can get either Harlequin Pants from the faction NM or the Claret's Breeches from the r45 dungeon.

For shoes, most Cons start with Padded Leather Duckbills or Toadskin Leggings. Again, the leggings have much better stats but no Con affinity. Eventually you will want to upgrade to the Warlock's Pattens from the r45 dungeon.

For accessories, I prefer one Electrum Choker and three Black Pearl Rings, although some Cons go with four Black Pearl Rings. If you don't want to pay the premium for Black Pearl Rings, regular Pearl Rings only have one less point of magic accuracy per ring.

The only Con abilities worth purchasing (in my opinion) are Fastcast (barely increases casting speed) and One With Nature (which is only useful on other classes). I have Elemental Shroud and Nature's Fury but literally never use them. But if you're doing leves, you're going to be ranking in enough guildmarks to purchase all the abilities anyway.

Goodluck.

As for Guild marks, I have also bought firm conviction (THA R30) to increase def while casting (usefull for solo) and out of sight (Archer R30) that reduces enmity generated by actions.