I think the advise for the climbing out child has been covered wellas for the cryer- I have (had) one too! I think sometimes it is a "first child" syndrome
my dkb was very sucky and clingy. I found ignoring the behaviour worked really well. Not to the point of hysterics- I would never let it go to that. but when he was trying to climb up my leg to hold him I would just walk away and not acknowledge him. It took about a week, but he now plays really well on his own. He is also a child who's parents would run the second he would fall and make a whimper. He learned really quickly I don't run at the drop of a hat- you need to really hurt yourself for me to come running
(don't get me wrong please- but I think we all know those children who do the cry for attention because of a tap... I still give lots of hugs for owies!). I think basically it is Ignore the bad/unwanted behaviour, reward the child when they are doing what you would like.