I think most people here post their graphic and want opinions on small constructive changes or something. That can be done when your graphic meets some basic standards, and unfortunately many graphics on RB has not been meeting those. Well today is your lucky day, as I'm going to reveal to you some check lists for you to follow that will elevate your graphics to meet those standards and allow you to actually allow some constructive feedback instead of people thinking it's trash or just not even worth critiquing. Obviously I have limited space to explain so this list only scratches the surface but it's a good starting point.
Good Graphic Checklist
1. Have a concept or purpose. People should "get" what you're trying to do with your graphic. Even if it's abstract, it should still communicate SOMETHING. Every dot, line, shape, color, etc has some meaning. People shouldn't look at your stuff and go, "WTF is he trying to do?" If your goal is to make something that is super confusing or something, you better have some deep purpose behind it, or you're just being random for random sake. And that's not art. Art should EXPRESS something.
2. Everything in your graphic should support your purpose. And everything should flow together in a meangingful way. Randomly placing a hotchick on some grunge background with some text just because you think it's cool = failure.
3. Placement of "things" and empty spaces should be interesting and create illusion of depth. Flat, unintersting, perfectly even and centered composition is boring. Have some constrasts(differences) between things and spaces between them to create excitement. Pay attention to the interaction between things and spaces.
4. Use the proper colors for your concept. Like I said, colors have different meanings. Use colors or combination of colors that communicate your concept best. Don't just use colors that you like. If your goal is to showcase some hot chick, don't colorize her face with some cold blue color cuz you think blue is cool.
5. Text. Make sure you select the right font for your concept. Study how different fonts have different meanings. Also don't just throw in many different fonts that you think look cool. More is not better. And just because a font looks cool by itself doesn't mean it will make the graphic as a whole look better. Everything has to flow together. And make sure text is EASY to READ!!! So many people on RB break this rule. If it's not easy to read, you fail. Saying, "You can't read that? You should be able to read that if you look closely" = fail. Unless your concept and intention is to make text hard to read and you have the skill level to pull this off elegantly, stick to the rule.
How to Give Good Feedback
Instead of focusing on your personal preferences, focus on HOW well the graphic was designed. Nobody gives a fuck if you like blue more than red. Nobody gives a fuck if you don't like the subject matter. Give feedback on how well the concept was executed and how clever the concept was developed.