I'll just take the advice that I took from another helpful person in my ponyless pennyless past of Spiral Knights.
If you don't have any idea which armor to pick, pick the one that will look coolest to you and head that way. As for weapons and stuff, I recommend the striker line because you can use the vile striker on jelly runs. (BUT I prefer the khorovod because of the knockback and I like em heavy) As for energy use, avoid reviving, try to get energy on market when prices are low (ask ponies if they are low or just put low offers, maybe 100 - 200 cr lower then average) and party!