Usually search engines will crawl pages from web portal, classifieds, social media websites more frequently than other normal service related websites so its good to get backlinks from portals, classifieds and social media sites so that our link will be crawled easily by search engines crawlers.
In order to do that we need to do promote our link in web portals, submit our classifieds ads in classified websites and make popular our website by promoting in social media sites like twitter, Facebook, LinkedIn etc. This is not only the way to get crawled frequently. There is another way to do that without doing this things.
The method of frequent content update to your blog or website will increase your search engine crawl rates, so its good to update fresh interesting content so that user also get in to your website and increase your Search engines crawl rate.