By interlinking, if you mean structure and navigation, it should be of the highest priority. Properly done, an inner page can rank highly based solely on your navigation links and structure. Additionally, it makes your site far more user friendly. Dave
Heck yeah, You need to pay particular attention. Most importantly is for humans. You can seriously increase the pageviews of websites by sending people to an interior, more targeted page, especially if you're using Adsense. More pageviews + better targeted ads. Always a winner
Don't forget to create a sitemap page on your site that lists all site's pages. It also will help to google to index your site faster
I haven't recorded any change for google but by a simple Home link with 2 keywords as anchor text MSN ranked me on 1st page and started bringing some traffic in.