From what i understand , i big part of Google indexing is to have links to your site in a lot of places.

for a eCommerce business, wanting to keep my site "clean" {clean being not full of spam and such}, how do i link it without spamming everything. shop comparison sites, forums, etc???

Forum signature, blog comments, directories
linking to internal pages is important as well

Try writing a good article submit it to EzineArticles, put your link in the author sig and I guarantee you will be indexed in maximum 36 hours.

You can do article writing, video marketing, blog comments etc. Try, in general, creating link pyramids and linkwheels around proper keywords on web 2.0 properties linking back to inner pages on your site.

You can control whether you are spamming or not.

Just focus on getting natural backlinks from quality sites and do social bookmarking, article submission and more.

Most important choose avenues that are related to what your are selling or optimizing like ex reg to car forums if you are selling car parts.

I recommend StumbleUpon, its the only bookmarking site I use anymore. I've been indexed within 20 min of bookmarking my site or a new article and still 2 years after StumbleUpon is providing 25% of the traffic to my website. No other site has even shown up as contributing in my Google Analytics.

Social bookmarking, Directory Submission, Article Submission and Article writing, Blog submission this all are essential for generating a backlink and to increase traffic as well as page rank. On page is really important for any site to get a good traffic and page rank.

Forums participation and blogging are a sure clean way to gain backlinks for your website.

Well, all SEO works has been done just for getting back links. Its depend us how we does this without spamming.

All should be done with white SEO hat techniques. Quality content with high ranking keywords surely helps to get much back links as well as high PR in Google.

Social Bookmarking is best way to Index in Google, also Article posting and Blog promotion help to get it right traffic from relevant area.

I can not write good article.. for me forum signatures work good.

It will only be a spamming when you do it unethically and against the search engines guidelines.

there are many ways, getting backlinks from:
forums
directories
social bookmarkings
articles
blogs

Establish the super connection on the Web page for others to click.the forums is a wonderful place.