Progress your campaign. Don't farm gear in campaign unless it's for a mission. Don't farm dungeons either if you are strong enough to continue campaign.

You will be able to farm same stars from dungeons soon.

Also, leveling and ranking up your main champion is more important than farming gear at that stage.

Your first big goals are finishing Campaign on Normal, Hard and Brutal and leveling your starting champion to 60.

You may also want to do what Progress missions, Challenges and quests ask you to do, so that you don't have to go back to do some "farm 3* hp% chestplate" later. I like doing every progress mission I can. It gives a sense of... progress :)

At 2 weeks 4* gear is as good as you can get.  Gauntlets and chestplate should be %.  Boots should be speed, unless you intend to break up sets.  

The previous replies are both on point and good advice, in addition : once you are in a place where you can farm gear of higher rarity ( rare and above ) from Dungeons you should prioritize Main stats and stars first, for example a 6 star common or uncommon pair of speed boots is better than legendary 4* flat attack or defense boots with good substats. 

You should aim for Epic or Legendary 3 star - 4 star - 5 star market pieces for the top 3 gears.

You should aim for Common or Uncommon 6 star campaign pieces for the bottom 3 gears.

Top 3 pieces are Sword - Helmet - Shield

Bottom 3 pieces are Gloves - Chest - Shoes

Top 3 pieces only get upgraded to +12

Bottom 3 pieces get upgraded to +16