Make sure you have something on your Tumblr page that interests people to read, like or share it to their friends. Post some questions and ask people to comment/write their opinions to your questions.
1. Now share your page on to social networking sites like Facebook, Twitter, Google Plus, LinkedIn etc. Make sure you share it to the specific groups/communities which are related to the same subject.
2. Bookmark your page in at least five leading social bookmarking sites. Make sure your bookmark is a public bookmark.
3. Submit your page to a couple of pinging engines which help the crawlers index the fresh content momentarily.
All these tasks may take some 10 to 20 minutes of your time but during this time you can expect Google to pick your page up into the index quickly from any of the sources where you have submitted