I got my Flame to +5, Club to +5 lightning, got Dawn's Circlet and bought the Bellowing Dragoncrest ring. All of that and I went from having four kings around me at 1/2 boss health to killing each with 20 seconds to spare. I really didn't expect those things to have such a huge impact. I got them all first try, and made plenty of mistakes.
Was this with your knight? Were you using buff spells on your weapon?
Being an SL1 Darkwraith really is the most fun you can have in this game. I usually just try to intimidate people, and really only try to kill their phantoms before I open up and drop my guard all the way down. There is so much variety. One invasion you're circling around an SL15 knight teasing them, the next you're in a delightfully honorable PvP match. I just wish there were still new people on though, I mostly only get long-time players doing new builds.
Low-level invading is a lot of fun, especially if you have gear around the same strength as theirs. Can't be reckless since everyone's so squishy.
My favorite is invading in the Duke's Archives. So much fun with the stairs.