The Rule Of Thirds

The rule of Thirds applies to a picture that has 3 different sections which are the: foreground, middle ground and background. The rule of Thirds divides the photo into a 3x3 grid, which allows you to gather the 3 main points of the image. It makes the images more appealing.The rule of thirds breaks a photo into parts. Usually the ground, horizon and background. Here is an example: 

The Golden ratio creates balance within a picture. This is mainly used when photos have a centre within it. For example if the image is in the middle and there are other things within the picture surrounding it within certain proxemics. The Golden Rule allows you to crop a picture with a more appealing composition. It can also be used to remove any unwanted things around it whilst keeping the important parts.

This theory came from a maths equation which balances the numbers out overall, and because things are balanced out, it became relevant for photography/editing as well.

When cropping on photoshop, the crop tool darkens the rest of the photo that hasn't been selected to be cropped. You can then choose the ratio of the crop size. This determines wether you want the picture to be portrait or landscape, and what size it will be when printing.
By clicking on the highlighted are of the picture, you can then drag it to the section that you want to be cropped.
The rule of thirds: This is when a grid appears on the picture , this allows you to get a better view of the: foreground, middle ground, and background.  

You can also straighten the image, this is when the horizon meets with one of the lines which will give the image a more accurate image either horizontally or vertically.