Do you want to avoid bad cocktails? Of course you do. David Wondrich, a preeminent cocktail authority of our time, recently published this article in the Daily Beast. It's entertaining, informative, and occasionally self deprecating. As a self styled "professional amateur" home bartender, it's good to know people with far more cocktail knowledge and sophistication than I have, e.g. David Wondrich (the author of Imbibe and other works), occasionally make colossal mistakes. It's sort of like watching a Gold Glove award winner in baseball boot an easy ground ball.
I heartily agree with Wondrich's classification of bad cocktails as either strategically bad or tactically bad. With the former the idea is a disaster, with the latter the idea is solid but the execution is a disaster. It happens to everyone. I am no exception. For example, the first time I made the Cancer Killer #2, I used too many orange bitters and damn near took out multiple people (my apologies to Ms. Cocktail Den, as well as my friends Ilan and Stephanie). After some tinkering a tactically bad cocktail became a good cocktail.
Let me paraphrase the advice I give to newer attorneys (I'm an attorney) -- It's not a question of if you will screw up a cocktail. The questions are when you will screw up, how badly you will screw up (it will make for a great story later), and most importantly, how you recover. Just keep on cocktailing!