NOTE, in 2019, the HTML title element you choose for your page, may not be what Google chooses to include in your SERP snippet. The search snippet title and description is very much QUERY & DEVICE dependant these days. Google often chooses what it thinks is the most relevant title for your search snippet, and it can use information from your page, or in links to that page, to create a very different SERP snippet title.
Your site’s URL structure can be important both from a tracking perspective (you can more easily segment data in reports using a segmented, logical URL structure), and a shareability standpoint (shorter, descriptive URLs are easier to copy and paste and tend to get mistakenly cut off less frequently). Again: don’t work to cram in as many keywords as possible; create a short, descriptive URL.
Ask for explanations if something is unclear. If an SEO creates deceptive or misleading content on your behalf, such as doorway pages or "throwaway" domains, your site could be removed entirely from Google's index. Ultimately, you are responsible for the actions of any companies you hire, so it's best to be sure you know exactly how they intend to "help" you. If an SEO has FTP access to your server, they should be willing to explain all the changes they are making to your site.
As of 2009, there are only a few large markets where Google is not the leading search engine. In most cases, when Google is not leading in a given market, it is lagging behind a local player. The most notable example markets are China, Japan, South Korea, Russia and the Czech Republic where respectively Baidu, Yahoo! Japan, Naver, Yandex and Seznam are market leaders.