I do graphic design and I want to know how can i create backgrounds that look natural as these
the first look like it was actually shot on a white background
but I find myself trying to replace backgrounds completely and they look so flat an photoshopped
I want a more natural feel like these

gradients in the layer you are using to give depth at what you want for the feel maybe?  Not sure of the effect you are wanting to reproduce,  sounds like you want what the shot should have had to begin with and you want to create that look post. Mo

There are a lot of way to go about this but I have some suggestions.

I start by filling a layer with a light gray then using a brush at maybe 20% opacity to lighten (with white) the center or darken the edges (with black). This will create a nice vignette. I suggest using a brush because a radial gradient will look very flat.

To add depth you can either use an image or a brush or both. You can find a image with a lot of value changes (darks and lights) desaturate it and apply a gaussian blur to it (30-60 depending on the photo). You can then lower the opacity of this layer until you get the desired look.

You can also download free photoshop brushes and brush texture into your background. The texture will add depth and if the edges of the brush are to sharp you can apply a light gaussian blur to that layer as well.

This is just one way that may help.

Perfect Effects from ONOne software is a cookie cutter program but it works and is well worth the price, use any magazine code they advertise for the discount sale price and it will give you want you want to do...and then you can learn to do it your way from scratch...with photoshop, paintshop, whatever works...Mo

great...liked the old version, now free...wow...will go there..Op-...check it out...Mo

...free is what you get...downloaded, teaser software to get you into their product line...disappointed in this marketing attempt by them, respected until this

https://www.youtube.com/watch?v=bc-1A-6tczs

This is a 2 minute tutorial on creating a gradient background.  It's a simple technique and will add depth to your background.

https://www.youtube.com/watch?v=DISXK-UfRYU