Hunny, you have to give people a little bit longer to reply - you only posted at 9.35am today!!!!!!
As far as french manicure is concerned, i dont use guides at all. It is a case of practice, practice and more practice (same as doing smile lines with l&p or gel) to get them perfect and then you dont have to worry about smudging. However, you can use Nailfresh (by Creative) or i use nail polish remover and a small brush to clean up with after applying the white. It is also very important to have a decent white ie. one that is not gloopy. A lot of them go like that very quickly but a lot of people recommend Cream Puff by Creative. Hope this helps.