The recommendations above will definitely be improvements.
The order in which I have gone in the past with great results is:
Placement
Treatment
Passive Bi Amplification
Spikes, or no Spikes?
Placement is FREE!, and is the most important. When I had my Vista speakers, it was only after deciding to take an entire day to remove all treatments and then move the speakers ALL OVER THE ROOM to find the best spot and orientation! This was the most successful tweak I had done up to that moment. they moved from being 3' from the panels to the front wall to 5-1/2'.
After the speakers were happy, it was now the right time to play with treatments.
Prior to the Placement Day I had already been using Passive Bi Amping. This however, is something that has greater returns at higher volume, at least in my experience, and this is why it's not anywhere near Number 1 on the list.
Spikes/Feet/Couple/De-couple is floor dependent and something that sounds good now, then go back to the other later, etc. For my Vistas I spiked to get more bass. And yes, I spiked into the wood floor - but only after that Placement Day I spoke about above. Up until then I used spikes on top of quarters. Now, with my current speakers, I use "spike shoes" with rubber bottoms under the spikes.