First to get an idea of how many links you may need, take a look at the top 10 ranking sites in Google and record how many links Yahoo is noting for each site. (This is because Google does not display anywhere near all the links they have noted). The average of this count is often a good indication of how many links your site may need.

There are many different ways to get links to your site including the age old reciprocal link trade, directory links, article based links, and links from press releases.

Reciprocal Links
Reciprocal linking has seen its value drop considerably over the past few years, however, if the site you are trading with is relevant you can still receive value from these links.

Paid Links
Google frowns on paid links, however that is not to say that they don't work. Often you can find highly reputable and relevant websites which are offering paid advertising spots. If these links are coded to link directly to your website without passing through any tracking redirects, you will in many cases see value in the form of both direct traffic and increased link densities and rankings.

Articles
Writing and distributing industry specific articles is a great way to help boost both your link counts and site traffic; for examples of such content see StepForth's SEO Blog News articles. Consider writing articles on a regular basis and submitting them to some of the more popular services such as EzineArticles. Be sure to include a link to your site from somewhere within the article, or at the very least within your bio. Try to use a target phrase as part of the anchor text for additional value.

Press Releases
If something of importance has happened to your company such as a new product launch, or other notable achievement - essentially anything news worthy, put out a press release. Submit this press release through services such as PRWeb or PRNewsWire. Again, be sure to include a target phrase as part of the anchor text.

There are also a number of places you can get links that have basically turned south, and are not generally recommended. These include signatures in form posts, guest books, and other typically free links.

Forum Posts
Forum posts can help to marginally raise your link counts; however, with this one you must be careful. Only add a link to your site in your signature if both the forum allows it, and you are a respected member of the forum. If you are a solid contributor and your posts have depth and meaning, and the forum is highly relevant to your site, then having a link in your signature may give your site some juice. Posting wildly to random forums will in most cases get yourself banned, and will be both a waste of time and potentially make you and your site look bad.

Guest Books
In nearly all cases, do not post your link to guest books. If you happen to stumble upon a guestbook that is highly relevant to your site, the other comments are relevant to your site, and you have something useful (and again relevant) to say, then perhaps consider it, but typically focusing on links from guest books is considered SPAM and is best avoided all together.

Blog Comments
Having a link from your blog comments is not necessarily a bad thing. If you find a relevant blog post of use, and have something relevant and constructive to say, don't be afraid to enter your link into the "URL" field of the form, but don't try stuffing links into the comment itself.

Link Farms & Bad Neighborhoods
These are sites that allow you to simply post your link no stríngs attached. They are mostly long scrolling pages with countless links. Stay away from them. If you see one, run in the other direction. These links are bad, will not help with your rankings, and in some cases can actually damage your rankings.

Stay away from sites that cross link with obvious spammers. These networks of SPAM sites are not ones you would want your site associated with, and if you achieve links from enough of these sites it can adversely impact your rankings. Even more important, NEVER link to any of these sites - as that will certainly tie in your connection to them and give Google reason to discount your rankings.

DMOZ, Yahoo and Other Directories
Directory based links can be of significant help, especially if they are from highly reputable directories, the two biggest being DMOZ.org and the Yahoo Directory.

Getting a site into DMOZ is like Gold. Google loves links from DMOZ and your site will reap the benefits. The big catch however is actually getting your site into the directory in the first place. Find the perfect category for your site and check to see if it has an editor. If you see a link "Volunteer to edit this category" try and find another relevant location. Pages without active editors take much longer to get listed into. Once you find the perfect directory submit your site every 4-6 months until listed. If you are lucky you will get in eventually.

Yahoo Directory is seen as an authority in the eyes of Google, and getting your site in will help your link reputation. This link does come at a price of $299 per year, but will play a role in helping your website achieve top rankings.

There are a number of other valuable directories out there that can help you with your search rankings. Before submittíng to any directory the key is a combination of relevance and authority. If the directory is relevant and active, it may be worth considering.

GOOGLE WEBMASTER TOOLS
Google Webmaster Tools can be very useful for your optimization efforts. It may not directly help you obtain higher rankings, but can help you trouble shoot if you are experiencing problems. It will also allow you to remove URL's that you don't want indexed and set various preferences such as your domain, crawl rate, and geographic target.

XML Sitemaps
This is the most common reason people use Google Webmaster Tools - the submission of their XML sitemap. While you can use your robots.txt to have Google find your XML sitemap, by submitting it directly to Google you can check up on the spidering status.

Error checking
Webmaster Tools is also quite useful for checking on various error URL's that Google may know about. Under the Diagnostics > Web Crawl you can view any errors that Google has to report on your site. By cleaning up any errors you can help boost your chances of rankings.

Links
From inside Google Webmaster Tools you can get a much clearer look at what sites Google is noting as having links to you, and give you a better indication of the need, if any, to raise your link counts.

WWW Preference
Be sure to select your domain preference under Tools > Set Preferred Domain. In nearly all cases you will want to select the version including the "www" .

SUMMARY
Inbound links play a significant role in successful Google rankings. By focusing on relevant links, as well as by diversifying where you get those links from, you can build a solid foundation for your search rankings today and into the future.

Stay tuned for Part 3 (of 3) where I will discuss other considerations including redirects, HTTP headers, and a number of other factors which play a role in successfully conquering Google.