| Like code to text ratio or keyword density, just forget all the "fancy" additions to the meta tags and get as basic as you can. KISS - Keep It Short and Simple Consider the following:
There is nothing as relevant as your keywords.
Meta tag construction is based on relevance, as done for my http://latelierart.com/ client.
Adding extra descriptive words in the meta tags decreases relevance.
Provide searchers with what they need. Save your sales pitch for your web page.
The following tags show in the search results as below. Tags
 Results: 
Notice how the first result is the shorter tail (Painting - Classes) and the 2nd listing is more definitive (Longer tail),
with the primary listing line reflecting the page's < title > tag.
<title>Adult Painting Classes, Broward County, Florida L'Atelier Fine Arts Studio LLCtitle>
Here is the site page.
Notice the use of the keywords in the header to reinforce the user's confidence that they have come to the right site. SEO for this area is important as it determines priority keywords and sets the site up for local search. 
The various colors represent conversion levels: Green - Top candidates for conversion, search includes all pertinent factors including location.
Orange - Search *could* result in conversion.
Red - Unlikely to convert Green - 8 out of 20 or 40% of visitors are likely to convert as their search criteria fills all necessary criteria including location.
Orange - 11 out of 20 or 55% show that client could benefit from presenting her classes as online courses or produced as a video for sale. Red - Only 1 out of 20 searches (5%) are too broad (short tailed) to convert. In this case the local search aspect is of utmost importance as clients will attend a brick and mortar location. Last 20 visitors by search data shows: 22 Apr, Wed, 21:59:14 Google: sculpture crafts Shows at #13, too general, (short tail) to be a good for a conversion. 23 Apr, Thu, 00:37:51 Google: painting classes broward #1 listing under 3 PPC ads. 37,000 competing sites. Excellent conversion possibility. 23 Apr, Thu, 14:31:08 Live.com: sculpture I could not find latelierart.com in the search results. Would have been a poor converter as it is too general. 24 Apr, Fri, 02:23:39 Google: l'atelier weston fl fine art studio #1 as it should be. 24 Apr, Fri, 20:47:38 Google: art lessons for kids broward florida #3 and keyword list has just been tweaked to include the word "art". 24 Apr, Fri, 21:56:20 Google: ART CLASSES BROWARD COUNTY #4 and same comments as above. 25 Apr, Sat, 04:03:15 Live.com: sculpture classes florida #1 out of 1,490,000 results. 25 Apr, Sat, 14:43:16 Yahoo: drawing classes for kids #1 of 8,990,000 sites. A bit too short tail to convert. 25 Apr, Sat, 18:40:20 Yahoo: adults art #2 out of 164,000,000 sites. Much too short tailed to convert. 25 Apr, Sat, 19:33:36 Google: public classes paint art broward county #5 and good candidate for conversion. 25 Apr, Sat, 20:55:06 Google: kid cart broward county #3, could be a convert but unsure as "cart" does not fit. 26 Apr, Sun, 20:25:20 Google: painting clases in broward #1 of about 57,900 for painting clases in broward 27 Apr, Mon, 16:15:43 Yahoo: drawing courses for kids #6 of about 6,690,000 27 Apr, Mon, 16:34:28 Google: drawing for teens #41 of about 11,200,000 for drawing for teens 27 Apr, Mon, 16:35:38 Google: art classes in broward #2 of about 56,000 27 Apr, Mon, 22:59:00 Yahoo: art classes for kids drawing drawing #1 of 2,930,000 results - Too general, unlikely to convert. 28 Apr, Tue, 03:35:59 Live.com: upcycling ideas for kids #27 of 22,000 results 28 Apr, Tue, 11:37:24 Google: art for kids broward florida #2 of 377,000 28 Apr, Tue, 15:54:14 Google: crafts for kids and adults #15 out of 870,000 28 Apr, Tue, 17:14:50 Yahoo: crafts classes for kids #2 out of 10,800,000 results | 
