Hey Lucio, nice looking minis...
I've been serious about painting since Nov/Dec of last year when I decided I needed better looking stuff...
Since then, I've made painting pretty much my second hobby... to the point where I moved a desk and chair into the living room so I could still hang out with the wife in the evenings....
I typically, paint the details, apply a wash, and highlight... I'm not at the point like LTP is where I'm 100% crisp... but I can see progress in my own paiting and that's enough. Thankfully, this is a hobby where you may never actually reach perfection.... And there's always somebody out there who puts your stuff to shame....
My advice would be to just keep painting stuff...
Also, if you're doing stuff in a production line, keep going back after you finish and look for things you could clean up, add detail to etc... For example, you could go back and paint the pouch on your tac marine.
Also, washes are great... Delven Mud, Gryphonne Sepia, Inks from Reaper (I use a lot of brown and Grey)
Here's an example of where I'm at right now... I know I have a ways to go but, it's where I'm at...