I have the same problem as you!!! my hair is really long... but its also quite thin! i agree that regular trims are good, but sometimes you need to do some extra things. One thing I have found is try to open your straightner/flat iron up a little when you get to the ends. Also, the shampoo you use is very important.
check out http://pamperstopcentral.blogspot.co.uk
my next post is actually about how shampoo's/conditioners can help xx