The following is a generalisation. We're talking about people here, not machines, but it's worth protecting yourself.
A manager's job is to control the workers under their supervision. They will do whatever they need to do to get the most value out of you possible. This means, if you want their help, you need to show them how you will be a better worker once they help you.
When they show you things, make notes. This makes them more understanding if you need them to cover things again, because it shows you tried to learn.
When discussing problem co-workers, explain how the problems are slowing down your ability to be productive. An obvious one is stating how feeling like you're in a hostile workplace makes you overly cautious and lacking in confidence. As such, you're slowing down because you're second guessing your work. Maybe the hostile work environment is distracting you and causing you to make mistakes. These all help promote your issue in their eyes.
Your boss is often your manager, but a boss' role is subtly different. A manager directly looks after the process that results in a product, a boss looks after the employees themselves in a team, making sure they have the resources required to solve problems.
A boss wants to know the team is working well. You need to tell them what you're lacking to complete your tasks, what's holding you back, and understand that they will always be comparing you to your colleagues.
If you have a problem with a manager, you'd approach your boss. If your manager is your boss, you might want to approach his boss, or HR.
To get the best results from a conversation with a boss, realise that you need to sell them your position. Requests to bosses often include a financial component - more training, new staff, even changing teams requires retraining and a replacement, and that's a loss of billable time. As such, sell them on why this change would be good, and you're more likely to succeed.
Human Resources is the company's legal defence. They Are Not Your Friend.
Seeing as HR are all about avoiding trouble, if you can show them that you genuinely care about an issue, and that you're protecting both the staff AND the company, you'll be making their lives easier, and they will love you.
If you're speaking to a new HR representative, you'll also find that they may genuinely believe that their job is to help the workers. It's always worth discussing an issue or two with HR that won't cause you trouble to see how they react to you.
From another perspective, if you are experiencing any serious problems, bullying or harassment, medical issues, or anything else that could result in you winning a lawsuit, HR are going to want to stop you. You can use this to your advantage.
As soon as you can show that you might have a valid lawsuit, HR will suddenly become far more receptive to your concerns. It'll be far faster, cheaper, and easier to get HR to handle your issue than hire a legal professional.