Planning internal linking for a bigger site

[idolw]

6 weeks ago a new version of one of my sites went online. Proper internal linking has not been planned before and I need to do it now.
The site's hom page is PR 5, google indexed 401 000 pages in 9 languages so far. Content is organised in several categories and subcategories.

I plan to use two types of internal linking techniques: linking from within content and linking from footer. Although in-content linking is easy as one can only link using ready text as links, I have a headache with the footer section. As the site is 400k pages big, I need to automate it.
As the website is divided into languages, I was thinking I'd link between the categories. Say, I have 6 categories in each language and I only interlink within the language. So my idea is to take a page from category 1 and link from it to randomly selected pages from categories 2-6. As an extra condition I'd avoid reciprocal links between pages and use wide array of anchor texts. That way Category 1 anchor text would not be just "Blue widgets" all around the site.

What do experts think?
Thanks

[Receptional Andy]

take a page from category 1 and link from it to randomly selected pages from categories 2-6

I'm not sure I understand the random element to the linking - IMO you'd be better off linking pages in category 1 to other pages within category 1. The ideal would be to interlink content that was more closely related, or based on how important a particular content item is within your site.

If you link between related themes, then the things you discuss most often naturally acquire a greater volume of links, and this is as it should be. You risk losing any kind of genuine hierarchy if you randomly link between unrelated content.

[idolw]

well, interlinking within a category already exists within standard navigation.

the entire site is within one topic so categories are complementary.

[Receptional Andy]

I would still look for some criteria in terms of when to link - ideally based on some kind of hierarchy of importance, or on closely related content.

[idolw]

Hi Andy,
thanks for your replies and help. I fully understand your advice in terms of how the web should look like.
However, when I look at the SERPs I see all the big guns blatantly place 100 internal links on each page and rule the SERPs for all low to medium competitive phrases.
I was thinking trying the same but on smaller scale would keep us safe and help a bit.

[tedster]

If you're not yet a big gun, and you want to compete with them - then why not finesse every advantage you can summon up. Quite often a top ranked site is ranking IN SPITE OF things they do, not because of them. And that opens up a competitive hole for you, if you can use it wisely.