Patience, and more patience, is key, no matter where our newly adopted dogs come from, they are not likely to behave in the manner we expect, they are likely to be 'cautious', stressed and confused until they begin to 'believe' what has happened to them is a good thing for them
Charlie was the most amazing 'teacher', I had a lot to learn, early on, he helped me understand that I had to let go of my 'expectations', what I thought I needed him 'to do' for me, and let him 'decide' what he was comfortable with. Had to let go of the notion of 'fixing' him, and focus on learning from him.
As with any, every, newly adopted dog, it took some time to discover what 'life' had taught him, 'who' he was, for him to 'tell' me, what he liked, was comfortable with, and what he was afraid of, he had a big list. His world was 'small' for a very long time, it was months before we could even venture out of the yard, helping him feel safe and happy at home was the first on the list, of what I could do for him. Giving him space, time to decide, some dogs will need more space and time than others, room to move away if he felt the need, the choice to approach if he would (or could), I always had treats in my pockets, for those special occasions, he wouldn't take them from my hand but would eat them off the floor.
Changing how they feel (counter conditioning- working to create positive associations) about the things they may be concerned about, many dogs will have just a few 'concerns', some will have more, but they can be worked through, let the dog set the pace, moving forward as they are able, goes a long ways to building the relationship and their trust. Whether it be, touch, the leash, the collar, being left home alone, new people, new dogs, slowly introducing them to new things, watching their body language will tell you how they 'feel', and if they are concerned, helping them learn that they are safe and going to be 'okay', in the presence of whatever it is, may take some time, patience and practice, but works to build their confidence, and their trust in you.
Give them the skills they need to fit into your life, take the time to teach them what you want them to know, don't assume they 'know' anything at all. Some adopted dogs have some skills under their belt, which they will reveal once they begin to settle in, some have not been given the opportunity to learn much at all. Keep it simple, to start with, don't ask for too much, keep it positive, make it easy for them to be successful, and reward them for the behaviors you want to see them repeat.
Take a moment to consider, from your newly adopted dog's perspective, what it might be like to have your world turned upside down, it is stressful, worrisome for them. They don't forget what their previous lives/experiences have taught them, the good or the not 'so good', (but they are willing to 'forgive', for some it may take some time), take a 'chance' on you, and move forward to a happy, fulfilling, and fun life with you.
Love them for 'who' they are, help them be all they can be.
A loving, trusting and valued member of your family.