Aw honey. Ok well there's loads that can be done. You may want to ask these people that said the above, why your stories are bad - plot, grammar, spelling? Are these the opinions of people that you value or internet people looking for an easy two points?
The Elements of Style is a great (and short) grammar book which might be worth a look at.
They say reading more will help with one's own writing.
Perhaps you just needed to revise what you had shown people - a first draft is rarely the best it can be.
When you watch TV look out for the techniques the scriptwriters have used. Notice how the dialogue flows, think about how you would write it should you have to write a scene similar. Try and predict what will happen next.
There are various websites with writing advice. Try looking up topics such as:
Using the active (rather than passive) voice
Showing rather than telling
Don't give up! That's the main thing. Good luck xxxxx