One of the main things that impresses social workers is experience. Yes, you've had a trainng, but do you know anyone who is parenting kids with special needs? Have you ever had a child in your home who has any issues? Have you ever sat down and talked to anyone (besides your social worker) who has parented a child like this?
Parenting experience is good, but often social workers don't believe that parenting "normal" kids, or parenting in a "normal" way is adequate preparation for parenting kids with a history of abuse and neglect. Even parenting adopted children who were adopted at birth or internationally doesn't necessarily mean that there it will be perceived that a family knows how to parent "system kids."
Now grant it, there are many children who are adopted internationally who have lots of issues: Fetal Alcohol Spectrum Disorder, Reactive Attachment Disorder, etc. But there are a great number of very emotionally healthy children adopted internationally, a sad statement. A Third World Orphanage has done a better job of raising many children than our foster care system has.
So, social workers want to see experience. They are impressed if you go to many trainings, and you should. The more you read, the better prepared you will be. Blogs like the ones listed on Adoption Blog Central can give you a look into the lives of people who are doing what you want to do, and that will help prepare. But social workers who are choosing a family for children want to see that you are willing to get yourself involved, hands on, BEFORE the kids are in your home.
Foster parenting is great experience. Doing respite care for another family who as adopted is also awesome experience. Spending time on a regular basis with a family who has adopted very hard kids is also very helpful (and a lot of adoptive families are kind of short on good friends, so they'd probably welcome the help).
One of the families that I worked with had a stay-at-home parent. While she was waiting to be matched she volunteered in the Emotional and Behavior Disorders classroom for a school year to get an idea of what kind of behaviors were associated with which diagnosis.
If you want to adopt cross culturally, it isn't enough to have a few ethnic dolls or artwork in your home. You need to KNOW some people of color. You need to associate with them on a regular basis. You need to have them be a part of your life. You need to ask them tough questions about racism. You need to work through your own attitudes about other cultures by being with people of that culture.
So, am I saying that if you don't do any of these things that you won't get matched? Not at all. But I am saying that you have to do something while you're waiting for that match, and these are excellent ways to understand what you're really going to go through when the time comes.
Don't fool yourself into thinking that you don't have time for any of the stuff that I just mentioned but that you will have time to invite a stranger into your home who is suddenly your child and be able to learn everything then. If you don't have time to add a few extra people into your life, you won't have time to parent the kind of children who come out of the foster care system.