My best advice is to look not at tutorials but real examples. There are plenty of resources for you to look at. Just keep practicing and get some feedback by posting here to see what areas you are lacking in. Tutorials only give you an idea of what you should do, but it's up to you to develop your own skills.
Arigato gintara-san hopefully i'll get better at it!!i wil not disappoint you!
Don't worry; you'll improve. It will take some time, but be patient with it.
Excellent advice from Gintara. But I'd like to add a small suggestion if I may; try googling "how to draw manga: female characters" That was a great foundation and did wonders for me. If you read through it, apply yourself, and really work with it you'll be able to draw a "babe" in no time.
Ummm... i dunno if this helps but... I tried copying and redrawing well drawn "babes" made by other artist and tried to memorize those curves and proportions by constant practice and i seem to improve a bit. Well, if you haven't tried it yet, do so. It might help... even if just a bit. Good Luck.