To target the obliques and the serratus successfully you would need to learn the basic anatomy. Many of the torso muscles are layered. The first layer is the transverse abdominis. The muscle fibres of this muscle run horizontally. When the muscle fibre shortens they squeeze in and pull the abdomen in. The next layer is your internal obliques. On top of it is the external obliques. The external and internal oblique muscles work together to rotate and side bend the trunk. Side bend exercises target those muscles.
Often mistake is to perform the side bend with dumbbells on both hands. In this case, the dumbbells are the resistance. Make sure to bend with one dumbbell so the obliques can do the work. Twisting crunches or rope crunches with a bit of a twist are another good example. If you want to emphasis on your obliques you can adopt cable wood chops.
The serratus originates from the back of the scapula and attaches to the ribs. The function of the serratus is to pull the scapula forward. Pull ups would be a great exercise for strengthening those muscles. I personally found dumbbell pullover very efficient for this muscles.
Many people believe that when targeting those body parts will reduce the body fat there. Unfortunately, you can’t target the fats and work on those muscles won’t remove your love handles.