If you have the Gunslinger Trials or Castithan Charge Pack DLC packs, you could isolate yourself to spend time leveling up weapons, your EGO level, and your EGO Grid Perks by going doing the arenas from either of those DLC packs in solo mode on whatever difficulty (probably normal) that you feel is appropriate. That way, you aren't running into other players by accident and getting smashed by higher Threat Level situations until you feel more prepared for them.

