Here is my template for the global titles and descriptions in yoast.
Quick Useful Link: http://www.quicksprout.com/the-advanced-guide-to-seo-chapter-4/
The following is a quick reference guide for the yoast variable options which can be used in titles and descriptions.
%%date%%
Replaced with the date of the post/page%%title%%
Replaced with the title of the post/page
*%%sitename%%
The site's name%%sitedesc%%
The site's tagline / description%%excerpt%%
Replaced with the post/page excerpt (or auto-generated if it does not exist)%%excerpt_only%%
Replaced with the post/page excerpt (without auto-generation)%%tag%%
Replaced with the current tag/tags%%category%%
Replaced with the post categories (comma separated)%%category_description%%
Replaced with the category description%%tag_description%%
Replaced with the tag description%%term_description%%
Replaced with the term description%%term_title%%
Replaced with the term name%%searchphrase%%
Replaced with the current search phrase%%sep%%
The separator defined in your theme's wp_title() tag.%%pt_single%%
Replaced with the post type single label%%pt_plural%%
Replaced with the post type plural label%%id%%
Replaced with the post/page ID%%name%%
Replaced with the post/page author's 'nicename'%%userid%%
Replaced with the post/page author's userid%%currenttime%%
Replaced with the current time%%currentdate%%
Replaced with the current date%%currentday%%
Replaced with the current day%%currentmonth%%
Replaced with the current month%%currentyear%%
Replaced with the current year%%page%%
Replaced with the current page number (i.e. page 2 of 4)%%pagetotal%%
Replaced with the current page total%%pagenumber%%
Replaced with the current page number%%caption%%
Attachment caption%%focuskw%%
Replaced with the posts focus keyword%%term404%%
Replaced with the slug which caused the 404%%cf_<custom-field-name>%%
Replaced with a posts custom field value%%ct_<custom-tax-name>%%
Replaced with a posts custom taxonomies, comma separated.%%ct_desc_<custom-tax-name>%%
Replaced with a custom taxonomies descriptionThese are the default titles & descriptions I use for the WordPress default titles and descriptions available in WordPress SEO by Yoast.
#####Homepage
Title: %%sitename%% %%sep%% %%sitedesc%%
Description: %%sitedesc%%
##POST TYPES
#####Posts
Title: %%title%% %%page%% %%sep%% %%category%% %%sep%% Blog %%sep%% %%sitename%%
Description: %%excerpt%%
#####Pages
Title: %%title%% %%page%% %%sep%% %%sitename%%
Description: %%excerpt%%
#####Media
Title: %%title%% %%caption%% %%sep%% %%sitename%%
Description: %%caption%%
##TAXONOMIES
#####Categories
Title: %%term_title%% Archives %%page%% %%sep%% Blog %%sep%% %%sitename%%
Description: %%category_description%%
#####Tags
Title: %%term_title%% Archives %%page%% %%sep%% Blog %%sep%% %%sitename%%
Description: %%term_description%%
#####Format
Title: %%term_title%% Archives %%page%% %%sep%% Blog %%sep%% %%sitename%%
Description: %%excerpt%%
##OTHER
#####Author Archives
Title: %%name%%, Author at %%sitename%% %%page%%
Description: Check out all the articles for %%sitename%% written by %%name%%.
#####Date Archives
Title: %%date%% %%page%% %%sep%% Blog %%sep%% %%sitename%%
Description: Check out all the articles for %%sitename%% written in %%date%%.
#####Search Pages
Title: You searched for %%searchphrase%% %%page%% %%sep%% %%sitename%%
#####404 Pages
Title: Page Not Found %%sep%% %%sitename%%
These are the default titles & descriptions I use when using the Testimonials by WooThemes Plugin.
#####Testimonial
Title: %%title%% %%cf__byline%% %%sep%% %%pt_single%% %%sep%% %%sitename%%
Description: Check out this great %%pt_single%% by %%title%% %%cf__byline%%. %%excerpt%% ...
#####Testimonials - CPT Archive
Title: %%pt_plural%% %%page%% %%sep%% %%sitename%%
Description: Check out all these great %%pt_plural%% for %%sitename%%.
#####Testimonials Categories
Title: %%term_title%% %%page%% %%sep%% %%pt_plural%% %%sep%% %%sitename%%
Description: Check out all these %%pt_plural%% for %%term_title%% on %%sitename%%. %%ct_desc_testimonial%%
These are the default titles & descriptions I use when using the Local SEO plugin. Note this is only available and used when doing multiple locations.
#####Yoast Local SEO CPT (Default CPT Name is Locations)
Title: %%title%% %%sep%% %%cf__wpseo_business_address%% %%cf__wpseo_business_city%%, %%cf__wpseo_business_state%%
%%cf__wpseo_business_zipcode%% %%cf__wpseo_business_country%% %%sep%% %%pt_single%% %%sep%% %%sitename%%
Description: %%excerpt%%
#####Yoast Local SEO CPT Archive Page (Default CPT Name is Locations)
Title: %%pt_plural%% %%page%% - %%sitename%%
Description: Find a list of all of our %%pt_plural%%.