I started fostering this month. the first dog we got was a disaster, just a terrible fit for my family, plus I had some unexpected health issues, so he had to go right away.
Can't wait to try again..
Any advice for a newbie?
Use a crate. Heavily limit the foster dog's freedom. With both kids and a cat, you have to be very careful about prey drive, "wild" mouthy play, and resource guarding issues. Food and chews given in crate until you get to know the pup. Never feed the foster or give valuable treat/chew in open space, certainly not around kids. Don't leave toys lying around.
More important - Figure out your "niche." There are common dogs that pass through foster homes on the way to adoption.
The wild/untrained adolescent - dogs surrounded between 6 months and 1 year once they are big, not cute puppies, and have never been taught manners (no mouthing, jumping, etc.). These dogs typically have high energy too. Many suffer from stupid breed restrictive laws (e.g., pit mixes).
The senior dog - lost home due to finances, life circumstance changes, sometimes people being terrible. May have medical needs.
Undersocialized shy dogs of any age - may come from being "outdoors" or hoarding situations. May just have never been taken out much (small dogs) and now can't be around children, noise, triggers, etc.
Young pup from unplanned litter - May be stray or surrendered. Likely under 6 months. Will adopt fast. Mostly an issue of housetraining and socialization.
There are all sorts of behavioral problems that are minor in one home and impossible in another, so it's mostly about figuring out what works for you. For example, dogs with serious separation anxiety can be tough to foster and adopt out. If someone is always home, you can serve an important need.
Sometimes it's really about the organization you are fostering for. What do they know about dogs they take in? How responsive are they to placing dogs in your home that match? You don't ever want to feel pressured to take a dog or that someone is minimizing your concerns. There is (sadly) always another group needing fosters if one is not respectful of your needs.