How would you do list building in small niches?

Not at all.

There's always much more beyond that point. Even in small niches, you can find creative ways to provide value whether it's a product, service, or just some helpful info/tips.

Think in terms of a relationship, meaning longevity. There's always a way to "build" beyond the initial point of contact or exchange. It's easier in some niches than other but it's certainly possible.

Let's take the two examples you offered. Losing arm fat and growing bigger tomatoes.

Losing arm fat:

They probably have fat elsewhere on their body. That opens up more possibilities. Then you can market dieting and exercising products. The market for the original niche is probably women. So you can move into helping them look and feel better. One other way to do that is with beauty products.

Bigger tomatoes:

The gardening niche is huge, too. And this is also about growing food. So there are tons of other foods, or those related to tomatoes. (Don't ask me, I don't really know.)

Regardless of what you do, develop a mailing list and at some point conduct a poll or survey. Ask them what they're interested in.

These small niches are generally part of the bigger niche.

If you become the expert in the small niche then branch out into the bigger area. If people know that you can grow the biggest tomatoes then what's stopping the same sort of knowledge being applied?

So in small niches once you've basically given them all their is in the niche, you should expand out and go a little big in the niche? Am I right?

There are different ways to build a list in the small niches. Like they said, it's usually one of the big niches out there. You can blog, advertise, do seo, social media, there's just so many to mention.

After that, once you get noticeable results, share them to your list for proof. You will then be seen as a leader/expert in that field. People will start following you and listening to what you say. Then it's up to you what you'd like to do next. You can even create your own products.

Just my opinion, but there's really 2 questions being asked here. First, how do you build (grow) your list, and second, how do you market beyond the first solution to a narrowly focused crowd.

As I see it, you gain trust through authority, and the easiest way you can gain authority is by becoming the go-to-guy within a very tight niche.

Let's use a hypothetical and say your niche is "hammering nails". You're not a master carpenter by any means, but when it comes to hammering nails you've set yourself up to be the first person everybody turns to.

For building/growing your list, you just have to remain focused on hammering nails. There will always be more/new people coming along who will want to learn how to hammer a nail like you do, and they will subscribe to your list to grab your insights and knowledge.

That's the answer to the first question.

For expanding your marketing to this list once you've solved their problem and shown them how to hammer a darn good nail, as others have basically pointed out already, you have to think vertically.

People who want to hammer nails real good will have other focuses and related problems that you can toss recommendations to. For example, it's a safe bet that the people on your nail hammering list work with wood.

So, here's where you leverage the trust you've gained by being the nail hammering authority, and tell your list about this great saw you've just used that gave you the straightest cut you've ever seen. Or tell them about the huge ebook of woodworking plans you just got your hands on.

In my opinion, this is the absolute best practice with regards to building your biz and revenues around a list asset. Because you've established yourself already as an expert and authority with your subscribers, and you solved the initial problem they came to you with, it's okay that you're not the go-to-saws-guy or go-to-woodworking-plans-guy, your subscribers already trust you and will give your recommendations the benefit of the doubt.

I would drive all that traffic straight to my sales letter page in some tight niches like those. You should expect a 1%-2% response rate if your sales letter is good.