There are many different ways to Photoshop an image. The key is using your judgement and eagle eyes as to which methods you see fit within the timeframe/budget while still making the end product look seamless and believable.
Always take ownership of your work by taking the extra time at the end to check your work or get a second opinion if you’ve been looking at it for too long.
Try to avoid the stamp tool if you’re not too savvy with it, chances are people will spot the repetition which will make them look harder to see what else is false.
I discovered a hilarious blog site over the weekend full of Photoshopping bloopers. I had hours of entertainment spotting the mistakes by rushed or inexperienced designers.
I hope you enjoy www.photoshopdisasters.blogspot.com as much as I do.
Here are a couple of examples from their site.
An X-Ray projector.
A missing reflection.
Your in Design,