Welcome to our little community! We are delighted to have you with us. Your website is interesting and I will comment as you request below. I hope, separate from that, you will also actively participate in sharing ideas and giving feedback as well as showing some favorite pictures....if you, by chance shoot too!
1. How can I improve the site?
The immediate impression is excellent. There needs to be consistency in having all the pictures work in the same way, so that we see a before and after.
If you reduce the size of these pictures a tad, they will load faster. The ket thing is to see the changes and get to the next image with no time delay.
I saw very nice work, especially the pictures of the folk at desks doing detailed jobs with relighting an entire scene. However other images, for example the lolly pop and the b.g. for the pictures with spots on were very flat and had no interesting features. Now, while that might be the wish of the client, it needs to be said, plain flat b.,g. requested by client. Those spots, are they made with any thickness and any edge. Lack of that height can give a sense of unreality. In some, the woman moved before and after and that lack of alignment is distracting unless, as in one picture with a necklace backwards, if I remember correctly, you have actually straightened her back curvature. Did you do that or are these not the identical starting picture?
2. How do you search for a retoucher when you need one? If you use a search engine, what keywords do you use?
I have used retouching services for a large institution in India because they are so inexpensive. But that was mostly just doing exact cutouts. I simply do a search under retouching in Craig's list or else just go to RetouchPro.com and see if I can glean some idea of who is doing good work. One of our French members uses a service in the U.K. for certain jobs, but in general most of us here can do our own retouching if we need to. But the majority here do little recomposition of already shot images.
A lot depends on what you can do. It might be useful to list tasks: cold correction, retouching, relighting, background exchange, skin touch up, cosmetic custom projects, restyling hair, body and face sculpting and so forth. After all, we need particular tasks that we may have neither the skills nor the time to undertake and you could likely do it faster.
Offer, perhaps a free color correction, skin smoothing or color correction as an inducement to get customers. Or else, trial with the edit being free if it can't be used.
Somehow, folk need to see you can do the work better or faster than they can and with less hassle than sending it to India.
This answers your question # 3 too!
I hope this initial pass over your website has been helpful!