Let me take you through the entire process of the publication of a game.
In case it's not crystal clear, you cannot submit an idea to a publisher, just like you can't submit an idea for a book to a book publisher. A publisher wants an actual game, just like a book publisher wants an actual written book.
You create your game, perfect it, and then you take it to a publisher.
Unusual strategies or shortcuts for publication/sale of your game will require huge effort on your part, and will almost certainly not work. Selling directly to shops, on a website, or from the back of your car, will fail dismally.
Just make a great game, and take it to a publisher. If it doesn't succeed, try other games, and other publishers. Or, don't try at all.
Household name publishers do not accept submissions. Start with a much smaller company.
As long as a smaller company has done a few games to a reasonable standard, and had them properly distributed to major markets, they're probably good enough to publish your game. If your game succeeds, a smaller publisher is quite capable of having large numbers of them printed, if the demand arises.
Make sure the company is appropriate for your game. Are they accepting submissions? If they don't specify, they probably are open to very good submissions.
There are a few websites that maintain lists of publishers that are accepting submissions. These places will usually charge a small fee.
Once you've chosen a publisher, you contact them, to propose your game to them. I'll cover the proposal process in another article.
About 5% of the time (very roughly, and varying greatly from game to game), the publisher will be interested in playing the game you've proposed. They'll ask you to send a physical copy of it to them by mail (or play it on Tabletop Simulator.)
The publisher plays the game. I've had this be almost instant, and also waited a whole year. Typically, it takes a couple of months. It's expected that you stop proposing your game to other companies, as this publisher is putting time into evaluating your game.
Some companies will never get back to you or respond, while others will write detailed feedback about their reasons for rejecting your game. This feedback is extremely valuable, and the publisher has gone out of their way to help you, by writing it. Even if you completely disagree, reply to them, thanking them. There's a reasonable chance you'll want to propose something to them again, so keep things friendly, and continue the email chain when you want to propose a game to them again. Writing back to tell a seasoned publisher that their feedback is wrong, and that your game actually is great, is an insult.
If the publisher does like the game, and thinks it's an appropriate fit for their company, they'll contact you, and have a chat. Publishers are also very much interested in you as a person. They have to work with you, so if you're a jerk, or are likely to be difficult, they'll reject your game even if it's good.
After this, the publisher hopefully agrees to publish the game.
The publisher provides a contract for you to sign.
Once you agree to publication, the publisher does everything from here: the artwork, manufacturing, distribution, and promotion (if any). You get a royalty typically around 5-8% of what they sell it for wholesale, which is about 35% of the retail price. This means your commission per game will be 2-3% of the retail price. This may not seem like a huge amount, but the publisher is giving you about a quarter of their profit.
A publisher may do significant development on the game. They may just publish your game as is.
The publisher will probably change the title and the theme.
They may change the rules, but will likely confer with you about this, and ask you to do it. They're highly likely to want to tweak individual cards or game elements. A publisher may want your involvement and approval. They may not.
The publisher likely has people and groups they use, for testing their games. These people and groups playtest the game, and check it for problems.
Your game will likely also join a queue. Publishers
will sign good games when they find them, not as they need them. This
means there will always be other games that need to be done before
yours. This queue is likely a year or more long. There's nothing you can
do about it. In the meantime, put more work into the game, or work on
other games.
Even after all this, publishers will hand back a portion of the games they've accepted. This is usually because the game had flaws they couldn't fix, but also for business and personal reasons.
Once development is complete, the publisher organises artwork and graphic design.
The publisher then sends the game to the manufacturer, who prints an initial print run. This is likely 2,000-10,000 copies, depending on the size of the publisher. The game is sent to distributors, and it appears in shops worldwide, and online. This takes a few months.
Sites like BoardGameGeek add the game to their listings, and reviewers start doing review videos and articles.
If the game sells well, the publisher does more and more print runs.
Most published games don't get beyond one print run, but successful
games can be reprinted indefinitely.
The publisher pays you your first commission. It could be the first
of many, or your last. Even successful games will peak, and sales will
decline over a few years, as new games come out.
If the game is a success, the publisher might be interested in making an expansion or series. Don't even think about such things now.
Publication is a long process. Expect a wait of two years at an absolute minimum, from signing the contract, to having the game in your hands. The upside is that you don't need to do anything except wait.
The publication process is so slow that you should have multiple completed games in process at once. Get to work!