It can be a difficult thing to communicate, but designers spend a lot of time trying to stress the importance of providing project feedback in an objective, brief-specific fashion.
You see a lot of graphic design and branding projects where the client takes a look at initial ideas and says things like "I don't like it", or ''I'd like to see some alternatives".
As any designer knows, this can be both soul destroying and really quite bewildering: without any kind of guidance, how can you do something more akin to what the client is expecting or envisioning? What seems to help is to try to really nail a brief down before starting a project, and then defend that brief and the designs that emerge from it to the client.
It's part of a designer's job to point out that a client is paying for a set of skills, expertise and a knowledge base and that any work produced isn't just based on drawing pretty pictures, it's based on research, time and effort in development and a clear understanding of how to meet a brief.
It's helpful to try and put together a visual way of presenting a project to a client.
So, for example, put together a Keynote presentation that shows the brief, and then highlights how your design meets the brief (a voiceover can often be the best way to achieve this).
It's also easier this way to challenge a client to really examine the design and tailor any feedback to be objective and based on the brief.
More often than not, clients can be much more responsive to this method and can offer some really constructive feedback for designers to work with.