I can use Photoshop and know HTML/CSS. But there are somethings which you only pick-up in the industry.
What resources would you recommend and how should I go about improving myself.
IMHO good web design is simple, accessible, and looks (and works) the same across multiple browsers/platforms.
Maybe start by reading a blog like this one http://www.kmhkreations.net/2011/10/12/10-tips-to-designing-... and then build off those ideas as you continue your quest.
As the author notes, "If you decide to follow these you may not achieve Internet success, but these tips will surely help you start out on the right foot."
Good design is an evolution. You will piece together other peoples work in new and interesting ways and others will improve on what they see from you. Spend A LOT of time on gallery sites looking at what works and try to replicate it in your next designs. Soon a style will form and good habits will be in place, at that point you can experiment with new things and give back to the community with fresh new design ideas.
Good luck mate!