I'd recommend snaring once or twice every fight while soloing, just for the s*** and giggle of it. If it still doesn't ever go up, then I'd say try snare-kiting the occasional mob for a few minutes, even if it's a low-level one so your spells actually land.
Worth a shot. That's how I keep mine up-ish (140 at level 17.5)... I'm not sure if it's recoverable when you're at 133 and level 40, though. I think skillups are based on the level of the mob compared to your level, so if it's fallen that far behind... *wince*
Good luck with it. I'm just glad I wasn't levelling when Conjuration was bugged and NEVER rose.
