There are certain times where you have to compare yourself competitive sport, powerlifting, bodybuilding but the majority of the time it's not worth letting it affect your progress.
Stop Comparing Yourself to...
Your favorite athleteProfessional athletes possess insane fitness levels matched by a great natural skillset, which is why they're considered elite. There's no point taking up sprinting and then two weeks later expect to smash Usain Bolt's world record.
You are your only competitor.
If you can run the 100m a couple of seconds quicker than a few months before, then you know it's working. It still may not be as good as Bolt's, but who cares?
Alternative: instead of beating yourself up over not being Usain Bolt, Cristiano Ronaldo or Odell Beckham Jr, why not look for interviews or focus pieces that they've done where they share their tips? You can use their advice to get the best out of yourself.
Anyone else in the gymDon't get jealous or competitive if the guy next to you in the gym is benching three plates either side of the bar. You will get there in the end - but work your way up gradually and leave the ego at the door.
Get the technique nailed first. A 60-70kg lift done with superb technique is far better than a 120kg one that looks like you're having a fit trying to control it. It took me a good few months of solid training to comfortably bench over 100kg!
Alternative: don't be afraid to ask for advice. If the gym intimidates you just remember that the strongest guy/girl in there felt like that at some point. You can always approach an instructor/trainer too.
Fitness magazines/cover modelsThat person on the cover may look awesome, but they will probably have a great deal of training experience. They may have also depleted water for the photo shoot, and gone extremely low carb for a short time.
They won't look like that day in day out! They may also be taking 'additional substances', which you should avoid unless a doctor advises it. After all this, pictures may be Photoshopped magazines want to sell copies so if that means sexing up an image, they will do it.
Alternative: similar to athletes, cover models will likely share their training tips either inside the mag or elsewhere online. There are even coaches out there who specialise in the contest prep/photo shoot ready look, if that's your thing.
Your friends and familyThe same applies to your girlfriend/boyfriend and best mate. You may live pretty much the same lifestyle, but it's still pointless comparing yourself to them. They may have started training long before you did. Genetics play a big part. Women will naturally hold a little more body fat than men, who will find it easier to add muscle due to testosterone.
There is also the issue of diet and food tolerance. What if they swear by a gluten-free diet but wheat sits well with you? Find what works for you. You also need to take activity level into account - their job may involve more lifting and walking than yours.
Alternative: work off each other. Compliment them if they're doing well and you may receive the same back. It always helps when the people around you the most are motivational and don't drain the life out of you.
So how do you judge progress?Planning and preparation. "Fail to prepare, prepare to fail," as the old saying goes. Find a diet that is healthy, flexible and fits within your targets.
If fat loss is your goal then a calorie deficit is needed, and carbs should be kept to the pre/post-training window. This will obviously change if you are looking to gain size or compete in sports.
When should you compare yourself to others?
In the right context. If you're competing in powerlifting or bodybuilding for instance, then of course you're going to have to see how you match up against others.