Step 1: Open up your photoshop as well as your picture (file>open). In this tutorial I’m going to use this picture.

Step 2: Then i crop/resize the picture to 245x320 pixels

Step 3: Duplicate the layer(layer>duplicate layer). Then Filter>Sharpen>Smart sharpen. Amount: 500 and Radius: 0.3

Step 4: Go to Filter>Texture>Grain. This is my setting

Step 5: Add psd/coloring to the pictures. This takes a lot of time for me to color. you can find some great psd here, here and many more at my resources page.

Step 6: I use this texture and set it to screen, opacity at 70% and fill 100%

Step 7: I use handwritten texture which you can find here. how to use it? set it to darken and after that i use sharpen the texture(filter>sharpen). 

tips: use the move tool to adjust the position and you can also rotate the texture!

Step 8: Flatten the image if you’re satisfied with the result(layer>flatten image). Save it and done!