Being that the title of a Page, Article and Blog Post should all have different values and characteristics, I'll limit my reply specifically too choosing the title of a "Blog Post".
Note: Depending on the goal of the particular post I can sometimes spend just as long, if not longer, creating the title than I do writing the post due to the importance of them.
1. Identify:
This is dependent on whether the blog post is for my own use, or whether it is one that I have created for a client.
I find it important to identify the reason behind the post and what it is providing to the reader. E.g: Is it purely informational, is it
promoting a product, is it suppose to increase a readers trust or is its purpose to make a reader complete a particular action such as signing up or further interacting.
Once I have identified the purpose of the post I can choose how to best word the title in order to better entice the readers.
2. Brainstorm:
I'll throw a few titles together that include characteristics that will appeal to target audience.
Example: If the purpose of the post is to make the reader act quickly to take advantage of a deal, sale or opportunity I'll write the title in a way that emphasizes urgency.
I particularly find strong verbs (or words in general) that fit in with purpose of the post.
3. Look Around:
I like taking a look at other posts that share similar content and see what those authors have done with their titles. I don't do this to copy a title, but I do it from a marketing point of view to see what is currently working well within that topic/niche.
4. Construct:
Once I'm happy that I can create a title that specifically portrays the post to its fullest and appeals to the correct audience I'll begin piecing together the titles created above until I have one that fits the best.
Most of all - I always try to write for PEOPLE. That's why it's perfect for me if I can write a title (eye-catching for people!) and with a keyword (perfect for Search Engines!).