I don't mind getting to know colleagues while on a break, but I'm not one who enjoys clubs or pub environments. It may just be that I'm a more introverted person who prefers to keep to himself when possible, and prefers to just have a small group of valuable friends.
the connections and networks you need to succeed in a proper job wont be built, solely, by having a chat over a coffee break and neither will keeping yourself to yourself. Also, being very cynical, being good at your job isnt enough. You have to know how to play the game and sometimes go outside what you are comfortable with to succeed. It isnt like the olden days described above but it isnt a meritocracy. Don't think that doing a good job alone will help you succeed. It wont. Obviously it will help but performance alone wont deliver success.
Identify where you have some weaknesses and try to find a way to work on them and improve them. BTW You aren't bad at those things. You just might never have had a chance to show your skills or you may not know to improve or had access to tools to help you. A decent employer will help you with that because they will see the benefit of you doing a better job. There are some really good tools out there on the net to help with this kind of thing. Try something like Belbin or the personality colours test ( there are LOADS like this out there)
It is good that you are self reflecting. That is really helpful, I find, in identifying areas for improvement. If you drop the ball (and we all do) admit that and learn from it. Don't focus on the result but focus on what you have learned and what you will do differently next time. Don't look to blame others when you should be standing up and accepting responsibility. Be honest, open and truthful ( but learn when people cant be trusted) and manage expectations about delivering. Saying you cant meet a deadline early ( and why) is much better than saying at the last minute. I have found most people will support you in that if you can say why early.
Also, to get very management speak, know what you are responsible for and what you are accountable for. The two are very different. Don't let someone push their accountability onto you. Don't try to push your accountability onto someone else.
University or College education is superb. However, university wont prepare you for the real world so take a mindset that you know nothing and listen to people who do. However don't be sacred to ask questions ( i encourage it and there is no such thing as a stupid question) and when you are confident challenge them with: why? Why are you doing that?
Finally, as said above, keep all the cleaners, maintenance men, security guards, receptionists and secretaries sweet. They are surprisingly well informed and often influential people. At the bottom line they can make your life an absolute misery if they want to
EDIT - that is a bit rambling but remember none of us knew any of this stuff before we started work and none of us know it all. Don't be scared to make your contribution. You have skills we don't. You have experiences we don't. That is the value we all have and we can all bring to work.
I joined the consultancy in my final role as Senior Head of Projects.
My job now is to argue with senior people like you and tell you things you don't like to hear.