If you guarantee payment this will have better results...

Converted to guaranteed payment    

Sir, any feedback would be beneficial to get you the desired look.

Regards,
Craig

Dear Madame/Sir,
I have submitted my designs.
I know you are busy but, would you mind to give me your feedback?
Please tell me if I am on the right track.
Thank you
Best regards,
Coco

I would appreciate your feedback. Thank you.

Why have I been sent an invite if you have already picked a shortlist?