There's two things I find that are the most common reasons for people failing to find their results.
1. BEING PARALYSED BY THE SIZE OF THE COMMITTMENT REQUIRED TO REACH THE GOAL.
The Solution: Break the ultimate goal down. You need to work your way up the ladder with small victories that take you one step at a time closer to what you really want long term. These mini wins act as check points for both tracking your progress and allowing you to stay motivated by knowing you're never too far away from a mini win.
2. CONVINCING THEMSELVES IT'S COMPLEX AND THEY'RE MISSING SOME MAGIC PART OF THE FORMULA.
The Solution: It's tough to not be drawn into the sparkly world of mass marketing that will lead you to believe you are missing something; the savvy fitness gadgets, the rapid weight loss shakes, the metabolism stoking pills and potions. Many find themselves chasing these fallacies rather than digging their heels in, doing the work and being patient. My advice is to be very mindful of who and what you follow on social media and to be very cynical of what you read/watch in the mass media about health and fitness. The real honest information is out there, but unfortunately it isn't as sexy as detoxing or the Cambridge diet.
If you don't know where to start and you want some clarity on your goals and what you need to do to start working towards them, seek out a professional Trainer. You don't necessarily need to part with a huge chunk of hard earnt cash for ongoing training assistance, you might just need some honest answers from someone who knows their stuff and who will tell you it exactly as it is.