A little learning is a dangerous thing and other idioms
A little learning is a dangerous thing simply means learn more! If you have had the smallest amount of training in a subject and claim to be an expert, you are setting yourself up for failure. Someone will expect you to know more than you do and you will simply fail. Many of us have learned "little" and claim to know much. Haven't you gotten into a sticky situation before where you made a fool of yourself because someone called you on your so called expertise? Therefore, it is important to learn much and speak less until you are certain you can back up your words.
He/sheis an ambulance chaser implies that a person chooses to become ill or seeks out ways to become injured so that they can "sue" for compensation. Unfortunately, I have met people like this and it's best to steer clear of them asap.
Asleep at the wheel refers to a person that never knows what they are doing. They seem to be in a fog. Not thinking ahead or forgetting their tasks. I hate to admit that I am sometimes asleep at the wheel myself if overly stressed!
Can't see the forest for the trees implies that a person is too wrapped up in details to notice everything before them. People like this don't weigh the consequences of their actions before they make a move. They often need someone to point out another perspective to them so they can step back and see what will happen before doing their job.
Charity begins at home states that no one is more important than family and therefore, your efforts should be directed toward those you are related to and emphasis should be directed toward their issues and problems first before helping friends. Don't know if I agree with this completely as some of my friends need more help than my family!
I've got your number has many different meanings. It could mean that you know the person's true intentions and they won't fool you. Or, it could mean that a person is in trouble and they better watch their step. Lastly, you know the person made a mistake and you will be sure to let others know if a change isn't made.
Old friends and old wine are best suggests that things we know well, are more dependable than newer, unknown situations.
Rake over old coals means that you need to let old problems or issues die. If you continuously bring them up, then you will bring the troubles and problems associated with them.
If you Sail close to the wind, you push things to the limit and are a risk taker when you make decisions.
If you Take the fifth you refuse to anser something.
These are just some idioms; there are thousands more. Hope you enjoyed!