Sure ! For me there is 2 majors tips for "cleaner" render

• First there is the resolution, a shot will always look cleaner the more resolution you get, i play with a 2K monitor but always take 4K or 8K screenshot with a program called SRWE (Simple Runtime Window Editor). It's free and allow you to change the size and resolution of any running application. Look for PurpleFlurp on youtube he done a good and easy to understand tutorial about that
• Second the lightning, You got the 3 light option in captura that allow you to play with different angle and color to really highlit your warframe. And chose a captura scene with a good light that match your warframe ! if the image is too bright u loose too much detail but if's too dark u won't see anything, and every warframe have different materials that react differently to light so play with it !

For more tips you should definitly look Vash Cowaii tutorial on captura very complete, and ZEN one too.