Hi , my staffie puppy is now 3months old we have had her since  weeks she is lovely nearly fully house trained sits. down and walks on a lead well , my only concern is she bites everything and everyone she seems to want to bite and play tug of war with sleeves, jeans , coats etc i raise my voice but nothing seems to stop her please help as she is now doing it to my daughters friend and ripping there clothes .

Have a read of the information in this link - I think you'll find it helpful.

> i raise my voice

Please don't!  It only serves to excite her more.

I would encourage the behaviour onto a toy (rope tuggies are good) take one with you when you go out and always have one to hand when you are at home.  Try not to shout at her or she may think you are 'joining in'.  Put her on a lead when people come to visit you so you can control her and not let her mouth people, place the toy in her mouth when she starts to get excited and when she would normally start to mouth and encourage her to play with it. If she has a favourite toy you could train with it as a reward too. Most staffies I have seen at our training club love tuggie games so work with it not against.  If the behaviour gets out of hand, give her some 'timeout' (behind a stairgate or crate until she calms down) but be sure you do not get cross, its not a punishment just a consequence of her actions.