Ususaly thats the same process I go through every year with my mom, I go and I never know what to get her(She's very picky, so I can't just get anything) so this year I decided to get her something useful . For example, she just got a new computer, so she is very into her computer, so I think I am going to get something relating to her computer for her. So my suggestion is, if your mom is into something , try a gift along those lines to kinda add to her hobby kinda thing.
Hope that helps
DGP~Honey~