Quit your job too soon
You may well hate your role and think that having no job would better than working another second in this miserable, stinking one but, believe us, in the vast majority of cases, it really isn't.
The old thought that it's easier to find a new job when you already have one is entirely true - being out of work has all sorts of connotations to it, so employers are bound to think you're a more appealing proposition when they know you're in employment.
Companies also look more favourably on candidates who don't have a CV full of job-hopping (or moving quickly from one role to the next). Understandably, once they've gone through the process of recruiting new staff, most companies don't want these employees to move on again after just a few months.
Be too honest on social media
When you're searching for a new job, there's so many advantages to being active on social media, but letting your potential future boss know exactly what you got up to last weekend probably isn't one of them.
One thing that many people come to regret about social media is being too vocal about their work issues. Telling your mates at the pub about why your hate your boss is perfectly normal. Doing the same online could result in you struggling to find a new job - or even getting sacked from your current one.
It's relatively routine now for companies to search candidates' Instagram and Twitter pages before employing them, so if there's anything that you wouldn't want them to see, now is the time to remove it - or, at a minimum, change your profiles' settings to private.
Have a ‘one size fits all' approach
Competition for certain jobs is intense to say the least, so it's absolutely essential to tailor your applications to fit each role. Study the job description, assess what they're looking for and make sure that your CV highlights all your relevant skills.
Also, if you're writing a cover letter, take the time to personalise it by finding out the recruiter's name - the little things really can make the difference.
Eager and passionate? Yes. Aggressive and scary? Maybe not. When you get to the interview stage, it's great to show some personality, but this really isn't the place to air your grievances about your old work colleagues.
Similarly, companies will love to see that a candidate is enthusiastic about the role, but don't push it too far and come off as being obsessive.
Pester, nag, hassle...
Talking of being obsessive, a fantastic way to completely blow any last remaining hopes of landing a new job is to hassle and pester your interviewer at all hours of the day.
Of course, if you haven't heard anything within a few days of the interview, then a quick follow-up call is absolutely fine and shows that you're definitely interested in the role, but anything more should probably be avoided. They won't have forgotten about you (although if they have, that's not exactly the best sign anyway...), so just leave them to deliberate and you'll find out as soon as a decision is made.