The change in color and size of the X can be recreated with a couple of keyframes, one pair for scale, one pair for color. Adding glow and adding keyframes for the properties you want to animate would do that.
The color overlay, the sepia tint and flash are just layers with blend modes. The flash could be created with a radial blur with the blend mode ADD and animated opacity, the tint change from a colored solid with the blend mode set to Color, or overlay. You could also achieve the tint with an adjustment layer and animated Hue and Saturation set to colorize, then animate the opacity of the adjustment layer.
If your camera is moving you'll need to do some simple tracking to line up the X's. Each X would be on a separate layer and you could create an animation preset for the color scale and glow change, then set the CTI to the right frame and apply the animation preset.
This is all very basic compositing and animating techniques. If you do not understand what I am talking about then search the help files for each thing I have mentioned by typing for example, blend mode in the search field at the top right corner of AE.