How can I provide effective feedback?

Providing good feedback will guarantee you great results. When providing feedback, there are a few rules you should stick to:

1. Make your feedback specific and actionable: 
   When the designer reads your feedback they should immediately know what elements of the design you like and do not like. The designer needs to know what changes they need to make - not guess them.
2. Make it constructive: 
   Simply telling a designer "I don't like it" is useless unless you explain why and how you feel it could be improved. If the designer is not on the right path then let them know. Better yet, try brainstorming some ideas to get them back on the right track. As a starting point, tell the designer what you like or dislike about the style, color, structure, typography (font) used etc.
3. Show encouragement where possible: 
   Try and identify areas of the design you like and let the designer know this. Providing some quick points on areas of the design that you find valuable might lead the designer down a path to a design that's perfect for you!  If you want to see more designs from them, let them know!