Hi,
I have 11 years experience on wordpress and 8 years on maegnto. I made a lot of sites uing wordpress and magento.
I use high quality coding, most optimized coding, search engine friendly coding, w3 validated coding, multi platform friendly coding.
After my work site will be high speedy to load, normally below 1 second. Site will be very good position on search engines.
To make a site HIGHEST POSSIBLE speedy I do:
Compress css/js/php files manually, minimize coding, optimize images, set apache server setting, validate coding, minimize server requests, remove bad coding, remove bad things for speed, merge js/css manually as many as possible etc. These techniques are mostly used by world top sites such as yahoo, msn, facebook etc. But other programmers do these using plugins or extensions.
How I make high quality site:
1. I use systematic coding.
2. I minimize coding as much as possible.
3. I compress coding.
4. I use search engine friendly coding. Jus one example of search engine friendly coding is using html tags like h1, h2 etc as many as possible.
4. I use coding which are good for loading speed.
5. I use optimized images.
6. I use compressed js,css and php files as many as possible.
7. W3 validated coding.
For the above techniques my sites are of high quality and more search engine friendly. Please check the quality of my sites on gtmetrix.com.