Just to preface this, I have been playing for a few months in 2 homebrewed campaigns, in which I feel I am doing okay but not as good as I could.

Q1: I play a bard (Level 8), and feel somewhat underwhelming. How do you play a bard and maximize its efficiency as the class. (Note: I know they're an awesome class but I can't get the most out of them with the knowledge I have)

Q2: How do Skills and Proficiencies work? We have 2 people besides the Dungeon Master who actually have Skills/Proficiencies and every time we play, we're rushed into the story and I have no time to do them (Or learn how to)

Q3: How do I tell my DM that I feel the storyline is too railroaded, and I'd like to see more Roleplaying opportunities?

Q4: How do I increase my health substantially? My health is by far the lowest in the whole group, so every time I get hit, I take a quarter to half my health in damage. I do have a relatively high AC compared to others in my group, but it feels like I still get hit easily.

Q5: My group just had a contract from a Hunters' Guild, and we killed a Rakshasa. Then, we were told that we were now marked for life by this Rakshasa. Besides going to the Level of Hell he'll reside in for a bit after he dies and killing him there, how can I get "unmarked".

Q6: Can you explain Prestige Classes and Multiclassing to me?

Thanks in advance to all who reply with any amount of answers to my questions. Please answer with the question you're answering before the statement so my brain can understand it. And thanks so much to my party (even though they most likely won't read this for getting me into D&D in the first place.

Edit: "2 months" to "a few months" Edit2: Playing 5e