G'day Johny!
Pretty good work there, considering you are new to this
Afew things I noticed mostly in the first colourization:
The portrait from the get go is quite soft/blurry, sharpening it up some BEFORE you colour it will make a big difference to your final result.
There is significant grey fringing (along hairline etc) bluring the edges of your selection masks (click on mask, select blur tool in tools palette and blur away!) or apply gaussian blur to the entire mask by alt(opt for Mac)-clicking on the mask, select all, Gaussian Blur (not too much, just enough to get an effective colour blend). I could elaborate more but I am pressed for time at the mo...I'll try to post more detail later on. You are doing great, keep a-practisin' and check out the
TUTORIALS on this site.
Cheers for now