Here's some fanart of solaire from Dark Souls, C&C will be aprreciated :).

Before you continue with this, you should really search for examples of decent sprite art so you can come to terms with what expectations people have with sprite art.

or you can give some helpful advice so that when he sees what "decent" spriteart is he can have something to GO ON to IMPROVE.

CnC:
While modern spriteart IS typically reductive in its efforts to represent the realistic world, I think you may have reduced a bit TOO much.

Just like how irl when the sun is behind you the outline of your silhouette becomes encased in what is known as "rim lighting (might want to look that up)" and the core of the figure becomes a tad bit darker it would help your image a LOT if you would do the same thing. I like the overall colors you chose here (Red Yellow Green White and Medium Grey) they go well together but try and add value to your art as well. Having all the red and all the white just 1 value makes the image you have here feel flat and overall "unimpressive". Adding value would not only solve this issue nut it would also give your picture a sense of volume. Right now the helmet of your Templar look like a square, then in reality Templar helmets are a lot more cylindrical . Go and look up how to shade basic 3dimensional geometric shapes using reflective light, diffuse lighting, cast shadows, core shadows, midtones, highlights etc. It will better help inform you on shading your pixel art if you ever want to do more.

While I wouldn't expect it at your current level you might even want to push yourself even further by attempting to add texture to your work next time. This would also be a big step in adding more to your art piece, though admittedly I hear its one of the harder things to do in sprite art.

Best of luck on your next try!

Quote from PLasmaghost

or you can give some helpful advice so that when he sees what "decent" spriteart is he can have something to GO ON to IMPROVE.

Yeah, my bad.
Alright, so the first thing that stands out to me is the whole thing is rather flat, and really geometric. The thing about sprite art is yes, you're obviously working in a grid-space, but restricting yourself to a certain size restricts you to a certain standard, so I'd recommend you also practice with a smaller grid-space. (Smaller pixels) Secondly is your use of colours, you're only using one colour per shape. You don't have to restrict yourself, as using lighting and shading with sprites is a common thing. (One thing to note is with sprites, is you can apply very vibrant and colour palettes that wouldn't look as appealing on normal artwork, so feel free to go nuts.) Your work is also very geometric and basic, which I don't like. The helmet being the one that stands out the most. As PLasmaghost stated, helmets aren't a strict rectangular shape. Try drawing it as a 3-D, more dynamic shape to give a better sense of depth and tone throughout. Although it's nothing more than a pet-peeve of mine, it's weird and inconsistent looking to have your art with certain sized pixels and text with another size. It looks lazy.

Also, what program are you using to make these?