You can update content, submit site map to webmaster tool. and do social media, it is helps to index your site.
Usually you must: 1. Building website with quality contents. 2. Regularly updated contents on the Web. 3. Optimize Urls. 4. Build backlinks. 5. Export a sitemap of site. 6. Submit your sitemap to Google Webmaster Tools
submitting a sitemap helps in this case. i heard somewhere that crawl rate is high for the sites which are updated often.