The first step is learning to understand your feelings. No one can make you feel anything. You and you alone are responsible for what you think and feel. Only when you fully grasp this concept, can you work to find solutions.
Step Two. Take responsibility. It's easy to blame others, but that rarely ever works. Even those who are the closest to you aren't responsible for how you feel. By taking responsibility, you turn a negative into a positive. Example: If you're feeling alone at party, instead of thinking, "No one knows I'm here. I might as well have stayed home." You can turn that around and tell yourself, "I'm happy that everyone is having such a great time that I can I don't need to feel pressured to contribute." This leaves you room to then decide if you want to seek out conversation, or not. Sometimes, simply observing or offering help to the host or hostess can be the most fulfilling way to spend your time. Some of the best parties I've ever attended, I've been little more than a "fly on the wall." (...a little frog humor.) Being an observer can be fun and illuminating.
Step Three. Look at your situation objectively. Humans, and a few of us frogs as well, often get so wrapped up in our emotions that we can no longer see the situation objectively. We begin to see through the hazy lens of fear, guilt, shame, etc. In these instances, it better to take a step back and look at the situation as if it were happening to a dear friend who was asking you for advice on handle it. What would you tell him or her?
Step Four. With paper and pencil in hand, sit down and make a list of the situations that make you feel uncomfortable. Next, make three columns; the first one will be the things you really want to change. The second list will be the things you want to change but have lesser urgency. The third column will be the things that might be nice to change but aren't crucial or don't have to be done right away. Now insert each of your uncomfortable situations into the appropriate column.
Step Five. Wait a couple of days and return to your list, Then check and see if you still agree with the priorities you've set down. It can be helpful, here, to consult with a confident. Try not to pick a friend or family member who will downplay your problems and try to make you feel like everything's fine. The best choice is someone who's experienced the same situation and has successfully found a solution.
Step Six. Make an action plan for each of your three columns. This is necessary even for your list of "nice to change, but not urgent." The point here is to exercise your imagination; to look for creative ways to solve your problem. There's no deadline, so take your time and write down as many creative and "out-of-the-box" solutions as you can come up with. And feel free to brainstorm with other people; two heads can often be better than one...especially if you're not used to thinking creatively. Just be sure not to lean on them for your answers. They can help, but remember it's your problem that you're trying to fix.
Here are a few simple suggestions that can help jump start change in the behaviors that be holding holding you back from enjoying social gatherings.
For example, If you feel neglected at parties: Go prepared with conversation starters like recent news stories, new books, etc. Keep standing. You avoid eye contact when you're seated. Walk up to someone and introduce yourself. Ask them what they do for work or how they know the host/hostess. Eavesdrop in on conversations and find one that interests you, then "hop" right in. You get the idea! There are similar ways ways to improve every situation where you feel invisible or just plain neglected. You just need to put on your thinking cap!
With a little creativity, effort, and time, you can change any situation from one where you feel alone in the crowd to one where you are happy, comfortable, and "fit right in."