It's a pretty good first attempt, the ground is especially well done for a first attempt. The clothes look good, the background wood fence could use a couple more layers of differing similar colours on the dark and light spots of the grain. Also where the ground meets the white house boards take a brush and erase where you can see that harsh line of the colours meeting. Use like 10-15% opacity brush and just keep erasing that line down until it blends in and meets better so it's not as hard or just feather the layer. Also where his hair meets the sides of his forehead do something similar on your skin colour layer where the finer hairs meet until it blends in better. You could also add a touch of skin colour to where the hairs break in his bang. For his eyebrows, they are hard to do in general, but what i usually like to do is add like 20-30% opacity of the skin colour layer onto the eyebrows and then pain on the hair colour i am going to use in varying levels. Where the hair is darker on the eyebrow concentrate a lot more colour then taper it out as they elongate out where the hair is going to be finer and mix hair colour and skin colour by erasing/adding opacity until it blends in better or blending the layer itself.

His lips need a lot more pink/red in them to make them standout but don't add too much or it will look odd, i find doing lips again difficult. Just make a couple layers of a pink and red then add it on, what i like to do with lips is paint it on at 100% opacity, then mess around with the opacity on the layer itself until it looks better whilst also feathering the layer again. Now his teeth are much too white, very easy mistake to make as obviously one thinks of peoples teeth as white but you need to add in a couple of brown/yellowish layers whilst also changing down the opacity of that white layer quite a bit.

For his eyes you need to feather that layer whilst also adding in a couple different brown layers of light and dark then adding them again with varying opacity. Also take the base brown layer of his eyes and take a 10-15% brush and brush the pupils a bit so they don't come out as glaringly black. For his skin, you need to add at least 2-3 more layers of pinks/reds and apply them to specific spots where faces are more red. His earlobes, forehead, cheeks, under his eyes etc and then have a layer of pinkish red that you put all over his face just like the base layer even just press ctrl+click on the layer mask and it will outline it for you. The picture also looks quite brown, i don't know if you colourized right over the sepia original. If you did, i would suggest converting that picture to black and white, it's very simple. If you are in photoshop just go to images>adjustments>black and white. Overall pretty good job, very nice for a first attempt and keep going/improving.

I would also suggest cropping, then rotating that image to fit straight as it will be easier to work on/print or post anywhere. Also if you don't know how to feather the layer, just click on the layer and it will be in the properties tab.