My experience is that if you email, most of them will be ignored. The best results I had was to put my paintings in the car. I would then plan a route of certain gallery and go in and request an appointment. If at all possible, or if I was asked, I could go and get my sample paintings from the car and get to see someone there and then. I've had a bit of success with this.
I'm saying all this assuming you've done your homework and you know the gallery will sell your kind of work. I would suggest that you make phonecalls. You'll have to ask them if they are looking to represent any new artists. A lot of them will say no.
If they say yes, then request an appointment. Make sure that when you go, you take business cards and your best work. This should be cohesive, ie not your experimental stuff and should look like it would be part of a series. Galleries like you to have a definite signature with your work because this makes it easier for them to sell it.
Also make sure that you have a price list of the prices you will want. The gallery will put between 40 to 60% on top of those but don't sell yourself short.
They will not charge you a fee. If they ask for this, then you walk away. It is not the normal way for galleries to operate and I have never paid anything. They are there to represent you and will hopefully make a nice amount of money from your work. An additional fee means they are not a great gallery.
Hope this helps.