You've written your book, maybe it's even out there in the world, maybe there's more than one. Now comes the bit where you have to find ways of getting people to buy it/them. For some people getting over the scariness of putting yourself out there is difficult. It can be daunting to know where to start. There is a lot of advice out there which in itself can be overwhelming.
Some things to bear in mind (only my opinion) check the links they might come in useful.
1.You are marketing yourself not the book - (ok hold the front page what is she on about?)
Some people (shock horror) may not like your latest release. This can be especially true for multi genre authors. More than one person has told me they marketed one book and sold copies of something completely different. If people have read the book you are promoting and they enjoyed your writing, or if your latest is not their thing, you popping up might remind them they were going to see what other books you have written (I have done the buy and read everything they've written thing a number of times myself.) If there's nothing that appeals at the moment, if they like you, they might buy something next time or at some point down the line.
People can be funny about buying books especially from unknowns and if you come across badly that can be door closed forever. I have bought books that weren't my thing because I liked the person, so it can work both ways. (Often it worked out well and I've surprised myself).
2. Each author and each book is different.
Unless you have written a series (and maybe even then) what worked for a previous book may not work for this one. What worked in the past may not work in the future. Also what worked for someone else may not work for you. This is why marketing advice is so difficult.
Read all the stuff, do all the courses, ask questions, listen and learn from as many people as you want and there may be nuggets you can use or not. There is no one size fits all magic marketing formula. If there was I'd tell you. The only way is trial and error which costs you in time and money. The good news is you learn along the way. I know more about who my reader is now, possibly, maybe. But with each book you are right back at the beginning (unless as I say you've written a series then maybe you can build on what you've learned up to a point anyway.) If it's the same genre that can help but not always.
3. Even traditionally published authors have to market.
If you think the publisher will do all the marketing for you, you're wrong. Sure it can open doors but its still your book and you have to push it. You are expected to be active on social media and have a decent following. (I'm not sure what numbers are thought to be decent - but your mum, your brother, your bestie and your aunty Jan and her mates are unlikely to cut it). Also be a bit careful what you post, people will see it, be authentic but if it's maybe unsuitable for your author brand get a private account in another name and keep that stuff there. Have fun and be human just keep it grandma friendly.
4. If someone you trust warns you off a site or a person - listen.
There are people out there who will take your money and tell you they can get you a certain amount of sales - they can't, no-one can.
5. As with most things trust your gut, ask loads of questions, and get some kind of agreement.
Never be persuaded into anything you are not comfortable doing. This is your reputation, your books and your life.
6. Books are forever.
If it doesn't sell out the gate, it still might. I've sold copies of my back catalogue that I thought would never sell another copy. I tried different stuff and it worked to a degree.
The links -
If you want your social media promoting to have a personal touch see if J.G. MacLeod can help you. If you follow her on Twitter then you will see she loves to promote her fellow writers. Get in touch https://www.fiverr.com/jgmacleod
David Gaughran keeps a list of promo sites that he personally recommends updated regularly. He only includes places that have been tried and tested and given great results. https://davidgaughran.com/best-promo-sites-books/ (Reminder that the results were for specific books so although the sites are trustworthy there can be no guarantee that they work for every book or every author). If you sign up to his newsletter you get access to his free course which I found very helpful and a free copy of his book Following.