Your operating in a extremely competitive niche, you will need to focus on getting pages online when they are fresh. Maybe get price comparison pages up way before the product has actually been launched to the public.
While Meta's and Content is important I believe these are the least of your problem, there are hundreds if not thousands of websites operating in this scene. Your going to have to work extremely hard to make the website successful.
I would consider the following in order to get your website ranking:
- Research Tail-Long Keyword Phrases
- Focus on fresh content and have it online way before your competitions, even for models that are not publicly available to the product. On the page just have the specifications, estimated page and then with a disclaimer or some sort saying this product is due in month X.
- Focus on social media, still today many websites ignore the power of social media.
I'm not going to go into the use of the metas, and content as I'm sure you already know this and I believe the problem you face isn't so much your content but outsmarting your competitors.