Making a Plan of Attack

Here I am today with another question that might sound silly to experienced players, but as a beginner I'm struggling to understand exactly how to plan an attack against the opponent's king and, even more to the point, when I should start coming up with a plan of attack.

When you go into a game, do you have any plan in mind? I don't really see how that is possible, but at this point, what do I know? Not much.

Do you start formulating a plan during the opening game? Do you wait to see if your opponent is going to castle before outlining a plan of attack? 

I know, of course, that any plan is subject to change. As a beginner, should I start thinking about plans of attack, or should I just concentrate more on learning to develop my pieces at this point? 

I hope someday I develop a bit of "spidey sense". 

@1

"how to plan an attack against the opponent's king"
++ By bringing more attackers than defenders and by eliminating the defenders

"when I should start coming up with a plan of attack"
++ When you control 3 of the 4 central squares d4, e4, d5, e5

"When you go into a game, do you have any plan in mind?"
++ No, it depends on what the opponent plays.

"Do you start formulating a plan during the opening game?" ++ Not yet, the opening is about  developing pieces into play, fighting for control over the center and bringing your king to safety

"Do you wait to see if your opponent is going to castle before outlining a plan of attack?"
++ No. If the opponent does not castle, his king in the center is vulnerable to attacks.

"As a beginner, should I start thinking about plans of attack, or should I just concentrate more on learning to develop my pieces at this point?"
++ First is not to lose: not to hang pieces or pawns and not put your own king in danger.
Second is to exploit mistakes by your opponent: take hanging pieces or pawns or attack his king when he puts it in jeopardy.

Thanks so much for these answers and this advice. I appreciate it! 

You are asking the right question! WHEN to attack is even more important than HOW to attack.

Many players... especially those who learned the game by playing Blitz... think that attacking brings you the advantage. This is quite incorrect.

You gain the advantage by maneuver. You cash it in by attacking.

Attacking is just a way of converting one form of advantage (eg: better development, center control and more space to deploy) into a different and more immediately useful advantage (eg: Checkmate or decisive win of material).

You might find this useful:

GM Larry Evans' method of static analysis - Chess Forums - Chess.com

As Boris Spassky said when asked which he preferred, Chess or Sex : "It depends on the position".

If the center is wide open, then castling should be a very high priority. If the center is not in an immediate crisis, development should probably take priority instead.

I completely agree.

I want to thank everyone who has responded to my question. The information is very helpful and gives me more ideas for improving my game.

I suck at chess. I really do. Sometimes I think there's no hope for me. And then I manage to win a game or two, and I start feeling hopeful again. It's a struggle. I'm taking it slow, watching the mistakes I make (by using game analysis) and trying NOT to repeat those same errors. 

I've learned a lot through the forum, and I have many more questions. I'm so grateful to be on a site where other players are willing to share their knowledge and assist beginners like me.

Thank you so very much!