Google Keyword Planner Help: What's Considered a Good Search Volume?

Higher search count with low competition is the best keyword to start with if you starting with a new blog.

For e..g
Search Volume - 30,000
Competition - Low

This competition is not the indicator of your keyword competition. It indicates how advertisers are competing with each other to win the top spot for that keyword

Google does not show you all the searches. I get visitors via keywords Google says nobody ever searches. Not many, but 4 from here, 30 from there, it adds up fast.

Don't think about a keyword. Think keyword groups. Not necessarily the ones Google gives you, but groups.

For instance:

ab machine
ab machines
ab machines for losing weight
abdominal fitness equipment
and so on.

Look up the total searches for all the keywords in the group.

Imagine together there are 10,000 a month.

That means that if the title of your pages, the meta description aren't piss poor, you're going to get some 3,000-3,500 visitors to your site if you have a page show up for each of the keywords in the number 1 position.

Then think about what you're selling/promoting. How much do you make a sale? How many visitors does it take you to make a sale?

Let's say, you make $1 per sale and you make 10 sales for each visitor to your site (the average website makes 1.5 to 2.5 sales for every 100), if the articles I've read are accurate.

So, if you have 3,300 visitors and you make 10 sales for every 100, then, you're making 330 sales a month.

At $1 a sale, you're making $330.

Now, it's time for you to decide if $330 warrants the effort.

Change my numbers with numbers you've gotten from other sites. If you've never had a site, never made online sales, keep in mind this:
the number 1 site gets some 33% of the traffic, usually.
The average website sells 1 or 2 of 100 visitors, a lot of people sell 0 and some sites (amazon.com, officedepot.com, sell 12-20 in 100 (again, based upon an article I read a long time ago). In other words, it's hard for you to tell.

But you have to start somewhere, so start somewhere below average, calculate as if you were average, then calculate as if you were 1 or 2% points above average and see if you like the numbers.

If you don't like any of the numbers, you ask yourself, is the experience worth anything? can I learn by doing so my next site will actually make me money? (The next site can be the same one with new pages for new keywords, assuming you don't totally screw up.)