A blog site will only be cached if Google crawls it from another website.Say you have a blog and you have submitted it to a directory.If the moderator of the directory approves your submission and is put in the front page of the relevant category there is every chance of your blogpost being cached.What really matters here is the blog platform that you are using.I use blogger and to my knowledge ten blogposts of mine are cached.Submit your blogposts to technorati or social bookmarking sites like digg and delicious to get it cached faster.Once that is done try re-directing visitors to your blogsite by adding a link to your blog from a forum or article directory.Once your blogposts starts getting traffic and it is content is relevant to the title there lies every chance of your blog improving in the SERP'S.Keep updating your blogposts with topics that are of interest.This will help. The Search Engine Ranking Position (SERP) of any website is more dependent on traffic garnered by that website for a Keyphrase or search tag searched in Google or any other major Search Engine.High Keyword density and a good title relevancy is a must.Rankings of a website in Google also depends if your website is cached by the spiders on a regular basis.Program your robot txt files such that they enable spiders to cralw and cache your index page.Keep adding fresh and original content to your website.Proper on-page and off page optimization is a must.A good SEO score further enhances your chances of obtaining a good position in rankings in Google.Get a Google analysis account for the website you are optimizing for and see the traffic sources.Monitor the keywords that are getting you the traffic and check for the keywords you want to rank for.Conduct a daily analysis and look for area where you are lagging and the areas you need to work upon.The rest is patience ...results are bound to come.