Blogging Advice

Can someone pass on some advice to a learner blogger on the following please:

- Is there a 'counter' that I can download or 'bolt on' to my blog to measure traffic? FYI - my blog is created through a blogger account

- What is the best way to increase your SEO, is it by 'linking' to other sites or by making comments and refering to your site - in an ethical way of course, rather than just spamming? Any comments or hints would be welcome.

Thanks

Nathan