I suspect that the voice, most often characterised by my mother and elder brothers, was simply perpetuating the 'myth' that I was only good for technical accounting, and anything creative was well beyond my kenning. It took years to quieten that voice to the point where it now remains almost silent.
I am my own worst critic when it comes to the issue of whether a story that I am working on is good enough to be published. I certainly don't need any help from anyone else in that regard. What I have learned over the course of the last seven years are the following habits (call them that) which have helped me enormously in gaining the confidence to put my work 'out there'. I hope very much that these pointers will assist you if you are suffering from the same sort of doubts that plagued my early attempts (and to some extent, still plague my efforts to excite and entertain).
1). I read as much and as widely as possible. I set myself the goal to read something every day - usually just before I go to bed. I read extensively in my own genre of #LGBT fiction, and specifically in the sub-genre of male contemporary romance. I also read poetry by the bucket load - it assists with imagery and the tempo of a scene - my favourite poets/playwrights are long since dead but still pack a powerful punch - John Donne, Andrew Marvel, Richard Fanshawe and of course, Shakespeare and Marlowe. I also read a lot of 19th century and early twentieth century literature, notably - Charles Dickens, Emile Zola, Agatha Christie, Joseph Conrad, Edgar Allen Poe, H G Wells, Camus and Edgar Rice Burroughs. I have studied the classics - old and new.
The principal reason (beyond the sheer enjoyment) is to acquire an appreciation of what is a 'good story'.
2). I have never studied, formally, writing technique, but in reading extensively, I feel much more confident in, for example, tackling a story in the first person (or from any perspective), using flashbacks, cutting in sub-stories, managing multiple timelines, etc. I would suggest a brief refresher in grammar and punctuation - if only to resolve, once and for all, the use of 'passed' and 'past' - I still get it wrong.
Being able to convert an idea into some written words, and entertain and excite someone else has been the joy, and the driving force, of my life for more than 6 years now. Long may it continue.
3). I take my inspiration from literally everywhere and everything - if the name of a brand of harissa paste can ignite a steampunk series then there is hope. I will sometimes make up a story out of the most innocuous of things and circumstances just to see where it goes - most of my stories are actually ignited by a line of dialogue - real or imaginary.
4). But, knowing what you enjoy the most is probably the key - I love romance - all of my stories have a central romantic relationship - every story is a human story, and almost every human story is born out of love, the search for it, and the end of it. It resonates with most people. I find I write the best romances when they are based, at least in part, on my own experiences - it adds a degree/level of realism.
So write what you enjoy writing not what you think will sell. I haven't written a vampire story, a shifter story or a full-blooded BDSM story ... and probably won't. I have read a few good ones, but generally, I prefer intrigue, suspense, crime and action thrillers.
5). Write more and talk less. The best advice I have been given, and give out frequently, is to write and don't edit as you go - leave the editing to the editing phase. Just write, take turns, go up blind alleys, jump canyons, dive over waterfalls - just write. Writing is a muscle that gets stronger with use.
6). Establish a routine for writing - a daily routine. I write mostly in the evening between 8 and 11pm - it's the quietest time of the day.
7). I do not use beta readers - I find their inputs too confusing and often conflicting. I do have a superlative editor. These days we have a pretty sound process for checking and preparing a manuscript for publishing - whatever your process, stick with it as consistency is more effective than constantly changing up the regime.
8). When it's done, it's done ... fear of putting a title out there is an all too present one - and this is where the critic usually has a field day. If I have followed my process, the story is ready, and after that, I get on with writing the next one. But first I celebrate (remember what James Caan's character Paul Sheldon in Misery does after he finishes a story?) It doesn't have to be a bottle of champagne and a cigarette ... it could be anything, but it marks the end and creates the space within which to give thanks for the story, the energy to write it and the assistance received to get it out - beta readers, editors, cover designers, publicists and marketeers also appreciate both a) knowing it is done, and b) thanks.
9). And get on with the next one - there is nothing an inner critic hates more than to be swamped by another and yet another story.
10). I am a heretic - do not read your good and/or bad reviews - there is nothing more toxic and nothing more likely to blow my creative candle out. Fundamentally, you cannot mandate what a reader is going to think about a story once it is out there - and think about it, what if you get a bad review; are you going to rewrite the story based on one person's opinion? And if you get a good review, are you going to be able to replicate that success without the risk of producing just a facsimile of the first - which will be panned by the critics.
11). Devote your energy to writing, reading and connecting with authors and readers.
12). Sometimes it can help to switch genres/sub-genres, write some poetry, write a play - throw everything up in the air and see what lands where.
13). Study other forms of art - I study all art forms, especially, film/photography, dance and animation.
14). Every inner critic has a source - find the source and cut it off. I showed my worst (real) critic the stack of 50+ titles I have so far published in my name and the 40+ more that I have been involved with as either translator, co-writer, editor/co-editor ... they don't question what I do and how well I do it any more. Most inner (and real) critics are fundamentally ignorant and jealous.
I cannot guarantee that you will silence your inner critic - I have silenced mine by adopting the habits described above. Does that mean that I sell more books? No. Does it mean that I get accolades? No. It means I don't doubt myself or distract myself from the highly enjoyable business of writing to excite and entertain a reader (in some place at some time - hopefully).