A little insight from a rescue.
Its very very true, rescues understand not all pets are a good fit everywhere, and most come with issues, so a "perfect" foster pet is Never immediate, it takes you, time, patience, and copious amounts of love and effort. But if you are not up to the task, they understand, if you are up to it, then Yay for all involved, sometimes all it takes is the right fosterhome, to show the pet that their previous life is behind them and not what a true love home is. DressAfford items that looks pretty to wear of the prom

Do some resarch on the breed of pet you want to foster, learn and be educated on how and what the specific rescue pet needs to be a good fit for a new home. Best training techniques for that breed ect. Ask questions!! Lots of questions so you are as informed as possible on the potential foster.

As a foster myself , and a rehab transition home for problem dogs, i know some are way more work than you anticipated, if you notice it or feel overwhelmed ( it happens often) , most rescues if you reach out they will work with you for solutions to the pets issues. ( training, behaviour mod, ect)

Are you up to the challenge?