At godaddy, you cannot install any server side software. Disable preview mode if you wish, as the name suggests it allows you to click the preview button and review setting changes before deploying them so your visitors can see the effects of them. If preview mode is disabled, changes take affect immediately or when the cache is emptied. Shared hosting is going to be arbitrarily slow because there are no dedicated resources for your site. Caching reduces the work that the server has to do, but again, you still do not have resources dedicated to serving your site. So what you can do is use minify and possibly add a content delivery network, but you still will have arbitrarily slow responses from godaddy for your HTML, which is what browsers request first when browsing sites as you know.
To be clear, I just went to: https://ismyblogworking.com/8020vision.com and saw:
The boring technical details:
Web hosting: godaddy.com
Server support link: godaddy.com
Server hostname: p3slh051.shr.phx3.secureserver.net
80 ms page generation time
240 ms page fetch time
98 KB/sec effective transfer speed
261 KB/sec burst download speed
80 ms feed generation time
110 ms feed fetch time
28 KB/sec effective feed transfer speed
0 KB/sec burst feed download speed
Page size (uncompressed): 80,444 bytes
Download size (compressed): 23,977 bytes
Bandwidth saved by compression: 70.2%
Content ratio: 54.0%
Blog If-Modified-Since response: 304
Feed If-None-Match response: 304
RSD URL: 8020vision.com
WLW manifest URL: 8020vision.com
WordPress theme: Thesis
Generator: www.remarpro.com 3.0.1
WordPress version: 3.0.1
Feature Supported?
RSS yes
RDF no
Atom no
Page Gzip yes
Feed Gzip yes
Page 304 yes
Feed 304 yes
robots.txt yes