i would talk to her about return of serve in doubles. if there is a lot of poaching it seems to really affect newer players. i think they see this huge person @ net and panic and get thrown all out of whack. my advice about that is to pick where you are going with each serve before the shot. for example: serve up the middle i go cross court, serve out wide i go down the line (or whatever she likes to do).
i would give her some major volley practice and tons of overheads. i found it easiest to go right at the net person's feet with my volleys.
oh, and don't forget the lobs. they come in handy when the pressure is on or if she finds herself being overpowered. i will try to think of some more stuff, me being fairly new to dubs myself.
3x Tecnifibre T-Fight 320 w/ Cyberflash mains-OG Micro crosses @ 55 and Yonex Supergrap.