@forest Skills Member,
CSS:
Via W3TC, manually combine CSS files, excluding any and all WooCommerce CSS files (These can almost never be minified/combined without some in-depth engineering).
As implied, first try “Combine only”. If nothing ‘breaks’ tick both “Preserved comment removal” and “Line break removal”; for @import handling use “Process”). Have a look at the site. If something is broken, revert back to “Combine only”.
JavaScript:
Use Autoptimize for your JavaScript. If something ‘breaks’, try following the instructions in the Autoptimize dashboard. If still broken after trouble shooting (shouldn’t be, though) you can try something like CloudFlare’s Rocket Loader.
Notes:
Make sure JavaScript minification is not enabled in W3TC and CSS minification is not enabled in Autoptimize.
Take your pick as to which of these plugins you want to minify HTML with (if you want to minify it, that is), also making sure that only one of these plugins is handling HTML minification.
^ Doing these things will likely solve the problem.
Best,
AJ