Another one that agrees with Bannick - it depends on the therapy. I think a range of various bodywork techniques can work for someone that does a form of bodywork (eg massage, IHM, reflexology, etc) and some techniques, you need something else, otherwise you start doing a non-standard way of doing treatments and still calling it by the traditional name because you're not trained in anything else (eg some people are very happy to have an IHM practice that is just done in a normal chair, when it starts being done on a couch it's getting a long way from what IHM is, people only trained in IHM seem to want to call it IHM still, people trained in another style of massage as well as IHM seem to be happy to call it a normal massage that includes some IHM techniques, similarly to how some massage therapists will do a short reflexology course, just to get some basic techniques that will enhance their foot massage).
Someone offering herbal medicine and massage you've got to wonder a bit what they are good at, someone that offers hypnotherapy and colon hydrotherapy you have to wonder about, there's got to be a bit of a sensible link (nutrition and colon hydrotherapy, you could understand).
Meridianmoon's way of deciding on the target market and getting the techniques to support that market is another way of doing it. You can be a one stop shop for a specialised market with a variety of techniques, trying to be a one stop shop for the general public is where you come across as a jack of all trades. A target market is a great way of getting clients, you just have to find them. eg a hypnotherapist/nutritionist that specialised in weight loss makes more sense than a hypnotherapist/nutritionist that speciallised in gambling issues (though there is probably a link, it's not a commonly associated combination). Which is what tigress said, clients are after a treatment for a condition, not a technique.
I started doing hot stone massage MANY years ago, no-one had heard of it, I'd say for the first 5 years the only people that made bookings were other therapists that were trying to decide if they wanted to train in it because they'd heard of it, it was only when the photos started appearing in magazines and any spa segment on a travel show on tv showed it that I had members of the general public making enquiries, and even then for a long time, it was mainly people buying gift certificates for someone rather than people ringing up and asking for a stone treatment. I've usually shifted people over to stone treatments after they've booked in for a massage and I will say 'stones would help with your xyz, do you want to try that next time?' I'll also add I am in a fairly religious right wing area and there is a lot of fear about stone massage! So it's probably not a good specialisation for this area, another point to consider!
Added: continuing education is VERY important - you need it, even if the course is not that good, networking with other people on the course is usually valuable. View continuing education as a way to enhance what you are doing, not a new speciality to add to what you do. You might decide that what you've learnt is so wonderful you want to specialise in it, but it should take more than one continuing education course to specialise in another technique....