Meta tags won’t help your Search Engine Optimization (SEO) because they don’t have an impact on your SEO ranking. However, meta descriptions can help because people may want to search/link/read more if the description is interesting.
The “title” portion of the img src tag is only useful to you. It allows you to give your images more description so you know what you’ve shown in your image. It is not at all used in SEO. On the other hand, the “alt” portion of the img src tag offers some help with SEO, but only in Google Images.
It is possible to over-optimize your blog or web site for SEO. If, for instance, you’re writing a post about cell phones, you may choose to use several variations of cell phone: cell phone, cellphone, mobile phone, Verizon, iPhone, etc. This can overwhelm your post because you’re using too many keywords in the hopes of stronger SEO. Your readers are turned off and not reading. Instead, focus on what is irresistable. What is the most interesting part of your post? What will make the readers more interested?
What not to do for SEO: Don’t micro-focus your posts. You’ll most likely end up with short, limited posts that read more like an advertisement. In turn, these types of posts rarely offer value.