not able to make things done

I agree with Martin. A lot of times our meshes are just too convoluted that trying to fix it is worst than starting over. You are going to sped too much time unraveling the mistakes. When you start over fresh, you gain speed and a better perspective of what you were doing wrong. And don't worry, that's how it goes at first when your starting to learn, we all have had to model something two, three, four or five times before we start getting the result we desire.