Be pacient with a tablet. Before you get it, you´re gonna think it´s going to be easy getting use to it, but it isn´t. You´ll need to practise a lot before you could get a nice and clean line but, let me tell you: You won´t need to be practising for a year, just practise everyday (Try to copy drawings or pictures on photoshop with a new layer above the picture with less opacity). Practise and be pacient!
That´s the key.