First photos... need an advice!

[roberthans]

Hello, professionals! I've just got started my first new camera (Nikon D3400) and there is so much to learn about it. Anyway, I tried to post several pictures on shutterstock (just for a portfolio, not for trade) and it didn`t even pass moderation. I just wonder how can I improve the quolity of my pictures? Is that so bad? Can it be possible with my camera? Or maybe it`s better to find another platform for newbies?

I didn't find the right solution from the internet.
References:
- http://www.thephotoforum.com/threads/first-photos-need-an-advice.412892/
- Professional Website Video Pricing

please help.
Thanks.