here's another tutorial i came up with from messing around with colours today!
TO THIS! 
> uses photoshop
> uses selective colouring
> follows seven (7) steps
* make sure your base image is not mainly one colour, or it will not look right!
1. crop your base, if you find it dark, duplicate your base and set the blend mode to screen 20%
2. sharpen your base, preferably with sharpen edges (filter >> sharpen >> sharpen edges)
3. open selective colour (layer >> new adjustment layer >> selective colouring) and follow this:
>> reds: -44, 0, -60, 0
>> neutrals: 0, 0, 0, -12
>> blacks: 0, 0, 0, +14
4. create a new layer and fill with #4EE0FF, and set blend mode to overlay 18%
5. create a new layer and fill with #00487B, and set blend mode to exclusion 40%
6. create another new layer and fill with #000000, and set blende mode to overlay 18%
7. flatten your image and you're done!
other images created with this tutorial:
> uses photoshop
> uses selective colouring
> follows seven (7) steps
* make sure your base image is not mainly one colour, or it will not look right!
1. crop your base, if you find it dark, duplicate your base and set the blend mode to screen 20%
2. sharpen your base, preferably with sharpen edges (filter >> sharpen >> sharpen edges)
3. open selective colour (layer >> new adjustment layer >> selective colouring) and follow this:
>> reds: -44, 0, -60, 0
>> neutrals: 0, 0, 0, -12
>> blacks: 0, 0, 0, +14
4. create a new layer and fill with #4EE0FF, and set blend mode to overlay 18%
5. create a new layer and fill with #00487B, and set blend mode to exclusion 40%
6. create another new layer and fill with #000000, and set blende mode to overlay 18%
7. flatten your image and you're done!
other images created with this tutorial: