Always keep the best gear that fits your required stats.

Blue items are good but there are some quests items (from Angmar specialy) that will give you same or better combinations.

Also, you can keep different jewelry, gear for different moments (raids, MP, Solo Play)

Gear with additional options with cooldown are ok but normally the cooldown makes it worthless.

Work on your traits to develop specific stats.

Find someone to craft new armor, jewelry and weapons. If you find some or in your kin get the right recipes and materials to reduce costs.