Start by adding your image into Gimp. You can do this by either dragging the image in from your files or clicking on File then clicking on Open and then selecting your image.
Click on the letter A in the toolbox, click and drag to make a text box and start writing.
Once you have chosen ur message, adjust size, make it bold and italic by clicking the little boxes under the font name.
Right click on the top layer (so the text) and merge down.
Then select the finger tool. This is the smudge tool, procede to smudge the letters. Try different tool sizes for a better affect.
Once you have done that, go to Colours then select Adjust Colour Balance. Select shadows and change the cyan value to 100, the magenta to 30 and the yellow to -30.
Switch to midtones and change the cyan to 100, the magenta to 30 and the yellow to -30.
Select highlights, change the cyan to 100 and the yellow to -100.