I used to do a fair amount of fostering of parrots. What I did when I brought one into my home is try to put their cage in a location where they had a long view of the room -- so it's harder to sneak up on them. Remember that they are prey animals and don't know if you want to eat them, so try to make her feel comfortable. I'd also try to announce when I was about to enter the room until I could tell they were comfortable (usually a few weeks.)
If they were really scared, I'd cover 1/4-1/2 of their cage so they could have a place to hide (makes them feel safer.) Even with my current birds, I hang a specific toy (a ring with fleece strips tied around it) near a high perch, and it's a place where my guys can go when they want to hide. Safety is paramount for these prey animals.
Also, in the beginning, I would try to not make too much direct eye contact. And I'd sit near them and just read, sometimes out loud to them, so they'd get used to my presence and see that I was non threatening.
And then, just watch her and follow her lead. Senegals (not always) tend to be a little more reserved, so she may always want to be more of an observer than a participant in things; or, she may be the life of the party! That's part of the fun of taking an adult rescue bird home -- the layers of the onion that you peel, until you finally uncover their personality. Watch her and pick up on what she's communicating to you. Figure out a way to communicate with her. Have fun! Updates, please!
ETA: lots of short interactions are much better than one long interaction. If you have 30 minutes to spend with her, it's better to do 2 minutes 15 times a day than 30 minutes all at once. Try to involve her in your daily life (even if it's just her watching and you telling her what's going on.) And of course, always be very careful of interactions that she has with your other birds or with your dogs, even though they may seem to get along, the size differences means a beak could easily be taken off a bird, or the dog could kill the bird (volunteering at the rescue, I have heard this happen dozens of times by customers...it's so sad. A bird I fostered for about 6 months was adopted out to a lady who left the bird out with her cat. After several years of no problems, the cat one day attacked and killed this poor conure. I still think of him every day and how it could have been prevented.)