How do I improve my website speed (Arcodding to Google Speed Insight)?

I'm not claiming that having a fast loading website isn't important -- but at a certain point you have to say, "Good enough." My guess is that you'd be better off developing your site (adding new features, content, etc.) or building traffic to your site than trying to score 100% on some arbitrary tool.

At the very least I'd ask myself these questions before spending any significant time tweaking my website trying to save a few milliseconds:
Have your visitors complained about your site loading time? Do you even have mechanisms in place to solicit this sort of feedback from your users? Is your speed likely hurting your search engine rankings and if so how much and does it really matter? (If you're like me other traffic methods are much more important than search engines). Is this really the best use of your time right now or are there other things you could be doing for your business that would be more catalytic?

Everyone wants good grades, but this is business not school. And in business some grades (like total profit) matter a lot more than others (like your website speed score).

If you're trying to squeeze every bit of speed that you can from your web site, visit here and you will find the tools to help you.

Steve

Jens,
IMHO everyone who is able to upload a file using FTP should be safe doing these simple modifications.
There is no magic behind this and for the minifications there are onlinetools you can employ using the normal copy paste functions.

Smushit is a good tool but shouldn't be switched on all the time.
I use it when optimizing an existing site. In the media menu in WP you find an entry 'Bulk Smush.it' which helps optimizing your existing image files.
Anyway, there are limitations as the webservice behind the plugin cannot deal with images bigger than 1 MB. I often see image files on the web that are a lot biger than 1 MB.
My approach is to optimize the image in Photoshop or a similar program. Reduce the size to what you really need and then save for use on the web. Compression (lowering the quality) doesn't have such a big effect on visible quality than everyone expects, but the savings in filesize are big.