Looks very good so far!
How are you doing the darkened seams and panel lines? Are you doing a wash and wiping off the excess? What are you using? Oils? Acrylics?
I like to use Tamiya paints thinned with their laquer thinner for all the base colors. Being a monotone finish (no camo)I go from dark to light. After primer I spray everything below the fender line black or in this case, black green.
Above the fenders I use this black green color to accent panel lines. Then I use the chosen color Tamiya XF 74, right from the jar, just sort of misting it on the lower areas. I "fill in" all the panels with the base color painting just up to the previously applied dark green.
XF 74 is a dark olive green that closely matches Marine Green from this era. I use Buff to subtly lighten the XF 74 and "fog" this into the center of panels and areas that would receive a lot of light. A bit more buff got sprayed onto the turret top, hatches, and wheel centers.
I usually coat the entire model with Future, then use extremely thinned oils to wash the seams. This one didn't get the Future, I let the paint cure for a week then used the oils. Due to the dark tones I mixed a bit of raw umber with black, then thinned it way out. I use a fine brush to place the oils into all the seams, panel lines, and nooks and crannies. If you look close you can see how the oils "bloomed" around the tool box handles a bit.This will disappear with a flat coat.
On a lighter colored tank, I'll paint it the same way with different shades accenting the panels and surfaces, but use the oils as an overall wash to tone it and blend the shading.
Camo has unique challenges as well. I'll paint the lightest color first, shading as before. Then I'll add the camo pattern, lightening those with various shades also.
Pershings had a cast turret and gun mantlet. I will use something like Mr. Surfacer to enhance the texture. This one came out looking real good so I drybrushed some Vallejo Khaki over the upper areas. It enhanced the cast texture, and added some highlights to the tank.
Sounds a lot more complicated than it is. What I am really doing is "color modulation" forcing light and shadow.