My DD (4.5) has always been the playing-along-side, rather than playing-with type. Recently, her nursery friends have started playing together a lot more, and DD seems really keen to join in. She's not excluded - most of the children are kind - but she doesn't seem to know how to join in. For example, on the way to school this morning we saw one of her friends and she was really pleased and ran towards this friend. But then she didn't really know what to do and either hung on to me or ran ahead being a bit silly (e.g., blowing raspberries) and didn't really talk to the friend at all. The friend ended up walking to school hand-in-hand with DS (2). This is very typical behaviour - she gets very excited about playing with friends, but then becomes overcome with shyness when she's with them.
Is there anything I can do to help her learn how to cope with these situations? Are there any books that can help? I know she might just grow out of this, but there are also people who are shy and find it hard to be included throughout their childhood, which is no fun at all.
Any advice would be much appreciated.