try a product, when your fall comes around, that we call in the states weed and feed. it specifically controls crabgrass with a particularly safe herbicide and gives your lawn a shot of feed to give it a fighting chance. to get those fancy rows takes time, mow your lawn in one direction and then the opposite direction the second time around, on the third time go back to the same direction as the first. keep repeating and you will get the look you are looking for after a few times around