i have three website one is magazine site and two are online shops i am updating my magazine site daily thats why that site is crawling by google daily but my online shops sites are not crawling daily even they crawled in a month so due to this in start of month site shows on first page of google search result but after 1 or 2 weeks they show on 2nd page of google search result, i want to know how i can link my these two shops sites with my magazine site from this when my magazine site will crawl by google as well as my shops sites will also crawl ,thanks
Do you hosted all the web sites in same IP? If not, check the web site loading speed. I think the problem is for your E-commerece web sites, as it is E-commerce sites it might have used some more Javascripts, if this is the case tell your developer to optimize the code and check the loading time. Compress your Js,Images folder. Also check the back links of web sites. Make sure you are not spamming keywords in your web site. Do a thorough check in Google web master tool and make sure that web site not containing any of duplicate title tags, meta-tags, content pages, product pages. If your magazine site is crawling more means just keep a link to your E commerce sites as well.
Try adding blogs or information sections to your online shop sites and write an article/post for them every few days about something related to what they are selling. Having the regularly updated content for Google to crawl, both the on-page text and the addition of the new pages, should help you get crawled more frequently with only a small time investment. If you aren't giving Google anything new to crawl, why would Google want to crawl them?
i think you need to check your site load which can be high try to decrease that as well as try to add a blog link on your site update that frequently as well as try to generate high page rank back links which will help you to crawl your site frequently.