A clause giving rescue the right to reclaim the dog if it is not properly cared for. It is helpful to have an attorney look at all your forms when you have them completed to assure that your liability is reduced as much as possible. The next thing to consider is fundraising. This is especially true for senior dogs and medically needy dogs. Unless you decide not to take these kinds of rescue dogs, you will need to have a fund raising plan.
Some groups solicit funds through newsletters, others sell or raffle off dog related items.
Whatever method you use, you will want to learn the laws in your state that cover fund raising. Remember, aggressive dogs are a safety issue and a liability issue. You will need to keep in mind that your ability to help dogs in the future may depend on your decisions today. Find support for those tough choices. It helps not to try and make them all by yourself.