Well personally i would just take some time for bonding, and getting to know the horse more yourself.
I tend to get mares ALL the time over geldings or stallions, for my own horse, i was hoping to get a nice warmblood or something gelding, but instead i ended up with a QH/DRAFT 4 year old mare lol !
The only mare i have had a problem with personally is pepper, who needs more training under her belt, and its hard to train a horse who has already had some bad habits learnt !
But personally start with just some basic things, like grooming, tieing, leading around, moving over when applying pressure. Etc, btw talking to them REALLY helps in my opinion :)
Eventually when you get their personality down and what they like over another thing, you can probably start making a list of things that need to be worked on, what you want to set for goals and what you want to start off with, things you know they will do well at (which is a better choice) and leave other harder things that take awhile aside.
Just any kind of training plan that fits them is going to get you along way !