My dd was a very prickly 11 yr old, and frankly, unpleasant to be around for a quite a few months. I realized that I was not spending really any positive time with her for a while, because she was sarcastic and nasty and I just didn't want to deal with that all the time. I had to make an effort to spend positive time with her. First, I picked things I knew she'd want to do - renting movies together (chick flick nights!) or going shopping for something, and then once we'd had some pleasant times together again, I started making an effort to keep her connected in other ways too, like cooking together, working on craft projects together, doing household tasks together. Once I made an effort to enjoy some time with her, she was more willing to do things with me, and our relationship slowly improved back to the closeness we had when she was a younger child. Now, we are much closer again, and able to talk all the time. I've found making an effort not to respond negatively when she tells me something keeps her talking more, too. So she'll tell me she didn't get a homework assignment done or something, and I don't get angry, just ask her how she's going to make it up, and ask if she needs any help from us, or whatever. She's much more likely to be open with us when we don't flip out about things.
My oldest ds was never as prickly as she was - he was easy to stay connected to because he obviously wanted me around. We used to jog together (he ended up running cross country in high school and I'd always been a runner) starting when he was 9 or 10, and I found he would tell me anything while we were running. He is very musical, playing several instruments and we played in a church band together for a while, which was a good connection as well. He always wanted me at his school events, would always volunteer me if a parent was needed to chaperone or something, and obviously wanted me. It was of course much easier to feel connected with him than it would have been if he did the more typical withdrawal from parents thing that my dd has done. He also was always very physically affectionate, liking to be hugged and touched. He still, away at college, ends every phone call or IM conversation by telling me he loves me.
My 12 yr old dd is not a very snuggly person - she never was as an infant, and she still is not the type to even come for a hug, let alone co-sleep anymore. Because she is not naturally very snuggly, I think it's important to make an effort to hug her, tell her I love her, and have some physical contact. I can tell she wants me to still express affection that way, but perhaps she thinks she's too old or something. She always seems pleased about some physical affection, though. I remember being her age and wishing my mom would do more with me, but somehow I never asked her to, and I think my dd is like that, too - only I'm not waiting for her to tell me she wants me around, I'm just assuming she does and participating in her life, if that makes sense.