What is the best url pattern for SEO?

What is the best url pattern for SEO?

I have a website with 1M monthly visitors site.com, with the following features:

• News site.com/news
• Videos site.com/videos
• Jobs site.com/jobs
• Events site.com/events
• Others... site.com/...

For the news feature: Each news is accessible under http://ift.tt/25HL4uH

For what I’ve understand, i should choose and create my category « category_name » for the keywords that i want to boost, so i'm going to move to http://ift.tt/1UrMJsE

Question:

• Am i wrong when thinking that i should add /category_name/ in my urls?
• Should I use more specifics category or globals one? . In our industry, there are many news about new applications such as « i.e: health/automotive/aerospace/finance » but inside health we have « i.e: dental, cells, bones »
• Should i not use category in my articles url, and just use the tags: http://ift.tt/25HM8Ph page accessible to list all the « health, dental, cells, art, bones, what-ever, company_name, .. » articles?
• Am I completely wrong in my understanding of seo?