Sit up and pay attention now. I know quite a bit about confidence and you'll be gettin' it in one swell foop. Hope you're rising to the occasion.
On the road to confidence, each piece of the puzzle offers the reward of a new world. Gaining confidence is not merely a struggle to get to zero as many assume.
Sometimes behind a lack of confidence is usually some sort of fear or assumption about the consequence of revealing thoughts, feelings or values. Such as, "If I get noticed, then I'll get squished like a pretty bug." Suspect these conclusions of "If....then...." Once conclusions get uncovered, check them out and see if they are really true. Many times these are mistaken assumptions and logical fallacies are involved. But if they are true, your question would be - how can I change this part I'm playing, maybe I'm feeding into this? How can I invite these what I want to experience from others?
Often feelings don't make sense. Reassurance can use the proof of reason and observation. Find out how to reassure yourself without having to lie or follow it with a snide remark. Figuring out how to do this will make anyone a better observer of what happens. Observation will tell the difference between responsibility and accidentally associated sequences that are circumstantially affecting outcomes.
Delivering reassurance to one's own fears may also teach a person to deliver effective compliments that can't be brushed aside or suspect. Remember, each new skill is a lie before you learn it. Don't worry if you have to "fake it 'til you make it."
If you said to a woman you admire, "you are so confident!" I'm sure she'd disagree with you, because women are taught that confidence is arrogance. (Women modestly often just get down to the business of doing what needs doing. The proof is in the pudding.) But if you offered your specific observation that, "Your openness works like a virus that disarms people," she might laugh and tell you about someone who wasn't affected in this way.
Often these mistaken conclusions involve mere opinions that are backed up with self-selected memories. This is a common phenomena that happens to many people when they feel bad. In a bad state, people often flicker through all similar situations of their past, seeking a factual basis of their own inadequacy or short-comings - or other suspected negative emotional state such as sadness, stupidity or thoughtlessness, etc. Questioning the point of doing this to yourself is productive. Never discount physical comfort as a contributing force.
The reptilian survival brain works in images. This part of the brain doesn't listen to linguistic qualifiers such as "Don't ...." Once you know more how this works, then you can also construct moments when you intentionally select the positive outcomes and positive effects of your compassionate and capable resourcefulness as well as other admirable qualities.Practice that for the thirty plus days it takes to change yourself - and you're good to go.
Because of the unknown and unpredictable nature of reality, it's easy to imagine that the contents of thoughts magically affect outcome. For instance, it's very common for someone to feel responsible for a death of a loved one in some way, even when they actually had nothing to do with it. You may find that it's not so much content, but it is the routine means of thinking that affects outcomes. Learn creative thinking skills. Be careful what you let yourself repeat, because you'll train yourself. ~It ain't what you do, it's the way that you do it. ~ as an old jazz song says.
Also, believe others when they tell you the positive ways about how you affect them. Absorb compliments when they come without imaging you'll suffer from evil effects. For instance, as a young girl I used to feel my mouth didn't look attractive. At thirteen, a cute young man in his mid-twenties saw me holding my mouth funny at a public function. He followed me around repeatedly, taking photos of my "beautiful" mouth while reciting how notable of an artist and photographer he was. I'm not sure he even had film in his old-format camera, but by doing so, he got me over a self-consciousness about my appearance.
After checking assumptions out about conclusions, if you decide they are true, you can deal with them in various ways. Often the consequence of the feared result is not all that bad as you imagined. If you try it voluntarily, you may actually prefer it. You can also regard the consequences if they're a force of nature and not pointed specifically against you. "You are not the target"- Laura Huxley.
One of my big discoveries in the process of losing my shyness (Me? Shy? You'd never believe that now!) was that other people were very self-involved, especially young people. The older ones are on auto-pilot. Most people are a product of their conditioning. They have much less control over the ways they effect others than they would prefer. Just as a surfer must figure out a few facts to ride a wave successfully, there are a few things you may be lacking to successfully navigate in the social world. Learn them and become aware enough to use them appropriately, without getting upset that you should already know these things. Forgive yourself. Nobody can help where they start from, but they can decide what they're going to do about it from now on. Just as a perfect wave doesn't care if it gets surfed, these factors, (that may involve people's reactions) may not care about your feelings, or even your survival. "Know thyself, then get over yourself" - Mr. Natural
A lack of confidence can be a defensive stance of hiding to protect...something. You may think you know what this "something" is, but usually the meat of it is hiding behind the reaction of shrinking, shirking or avoidance. This takes persistence to uncover. Trace the reaction back to right before it's about to happen, and there you'll find the original feelings that put the hiding, shy or shirking solution in place. Of course, your reactive solution was viable at the time you designed it originally. It only later became obsolete. Now that you've grown and know the origin, you can choose another way. The habitually reactive solution is still there to use in a pinch.
Sometimes you can just ask people, "How do I affect you?" But beware of setting in place a tacit agreement that you'll always be agreeable. The danger of asking is then the responsibility will be on your shoulders to accommodate other people's short-comings that you supposedly "caused." It's never a good thing to allow fears or short-comings to run the course of relationships, whether they be personal or social.
Finally, observe the positive state in others you want to embody and note how they express it. Quiz them. Try stating these observations positively, not merely stating them by defining what you do not want. If can't you say what you want completely or only in a metaphor (as you've done by saying it's a colored attitude,) you can always find more practical evidence of how it actually works as you move toward it.
One of my most useful observations about happiness came from realizing that it's subtle, calm qualities were very different from the strong intensities of my imperative need to rebel against unhappiness. Happy confidence was not a dizzy, drunk intensity - it was curious, quiet, unassuming & absorbed. This has turned out to be true for other topics as well. The positive expression of what is desired probably won't have the same qualities of what you don't want.
For instance, if you realized that modesty and being humble are expressions of confidence, make observations about how are those qualities expressed in behavior. What happened when these expressions of that value were practiced by you? Did they have the intended results on others and the situation? Did things improve when you gave up specifying results? As you gain more experience in the world, how might you improve the expression of your values as they become more refined, flexible and sophisticated?
The ability to ask questions, personal questions about yourself is a sign of strength and admirable character. Vulnerability is an asset. You can reinterpret the "heat" that might come your way for doing so as respect - and sometimes people are threatened by confidence. Enjoy before integration.