SEM
Search Engine Marketing (SEM) is the process of competing with others on search engines to display your website over theirs using money. Advertising online is a major key to success nowadays since its very hard for someone to come across your products when they are bombarded with others that have paid to have their pop up before yours. Thats where SEM comes into play, one of the best andc most effective way to promote your site.

Keyword Optimization
Paying for SEM is not as simple and effective if you lack certain criteria. One of the most major things you should focus on is using the best keywords possible for your Ad. for example if you are selling Bass Taxidermy, you would want to use keywords such as Taxidermy, Bass Taxidermy, or maybe even Fish art display for customers who don’t know what a Taxidermy is. Putting in the correct keywords for your products and or site will make or break if your Ad shows up on search engines.

PPC
Pay Per Click (PPC) is one way you can advertise your adds through SEM. PPC charges you per every click that is generated on the Ad, It is more cost effective hence you are only paying for the people that end up clicking on your websites Ad rather than paying a flat fee and have no traffic for your site.
CPM
Cost per mile (CPM) is the other way of advertising through SEM. With CPM you are paying a flat cost per every thousand impressions your ad makes. An impression does not mean a click or visit to your site. It is rather just your ad popping up on the Search engine and being seen by people. This is alm ost the opposite of PPC.