Changing my Blog

Hi,

I am a fine artist and want to make some serious content changes to my blog – deleting most of my earlier posts and pictures in order to update it to be and look more professional. Other than making the blog private while I am renovating and canceling trackbacks and pingbacks, are there any tips or pointers you can give me – such as plugins which might come in handy in this process? I am also most interested in not having Google direct people to old and deleted blog posts going forward. Any info on that would be greatly appreciated! Thank you.