Martin sums it up with these points -
4. You're doing too much shit.
Be a minimalist, like me.
I snapped this yesterday and stay in this condition all year round.
I built my physique with these movements primarily: squats, deadlifts, bench presses, chin-ups, triceps extensions and calf raises. These have remained staples throughout the years. I have flirted with other movements, but these were brief periods.
On the whole, that's one movement per muscle group, with the exception of abs and biceps, which I never really trained except for early in my training career, and then very sporadically every once in a while.
The point is that most people are doing too much shit. This dilutes the focus and effort that they are able to put into that which really delivers.
5. You think more about supplements than squats.
No single factor in strength training receives so much attention, yet deliver so little in return. Don't play the fool who chases magic pills, thinking it will compensate for a lack of effort, a fundamentally flawed training routine or a poor diet.
There are supplements that you might actually find useful, but they won't turn the tide if what you're doing right now is not working without them.
6. You're lifting weights for the calorie burn.
Strength is strength. Cardio is cardio. Don't mix, keep them separate, and use cardio sparingly on a diet or if your primary goal is strength and muscle gain.
If you're adding 2-3 sessions of HIIT to your 3 sessions of weights, it is almost comparable to adding 2-3 days of weights. Keyword is "almost", I'm obviously not drawing direct comparisons. That's all fine and dandy if you think working out 5-6 days/week is a good idea on a diet. But I don't think anyone - no matter what level of experience - needs more than 3 days a week in the gym when cutting. (Yes, this goes for competitors and beginners alike.)
In conclusion, if conditioning is not terribly important for you, if your goal is really about getting shredded while keeping your muscle, I highly suggest limiting moderate to high intensity cardio on a diet - or ditch it completely. Save it for some other time when your recovery is good and not limited by your diet.
A calorie deficit is a recovery deficit. Avoid deficit spending.
7. You're looking a bit too happy in there.
If you're not grimacing, grunting, or experiencing some sort of discomfort, you're not training hard enough. One good set where you have to fight for the reps is better than a week of half-ass sets.
8. You spend more than 5 minutes on abs.
If you can't see your abs, you need to unfatten yourself. Simple as that. You can't spot reduce and you'll get plenty of ab work with squats, deadlifts, chin-ups and overhead presses. Let me see someone at 5-6% body fat deadlift 2.5-3 x body weight for reps with with weak abs and underdeveloped abs. It ain't happening.
I'll allow you one set of "abs". Beyond that don't waste your time with crunches, ab machines, hanging leg raises or whatever the hell you're doing. It won't give you shit and it will only suck time and energy from what you should be doing.
10. You're afraid of "bulky muscles" and use terms like "toning."