When possible, on your website, link to your Tumblr blog.
But don’t make it passive, like “Please visit me on Tumblr.”
Make it a content upgrade. So whatever you’re telling somebody about on your site, try to complete the information on Tumblr from time to time.
For example: on your main site, maybe you’re telling people about how to take advantage of a seller’s market. You can say, “there are 5 things that will really boost your sale…”
Then tell them 2 things, and say, “if you’d like to see the other 3 things, click here” and then link them over to your Tumblr blog.