If, you ticked any of these questions - you could be halting your progress
Question 1. Never spend more than 45 minutes to an hour in one training session. Make sure to only train once a day
Question 2. Only use enough weight for 8-12 reps. Don't show off, it does not impress anyone, and its not helping your progress.
Question 3.Partial reps do NOT help slow gainers. These are movements used only by competition bodybuilders. Make sure you only do full movements.
Question 4. Overtraining a muscle group, will actually make it smaller. One exercise per muscle group is best - two is the most you should do.
Question 5. If, you are a Slow Gainer - stick to basic exercises i.e. squats, bench presses and deadlifts. Isolation exercises will only stress out your muscles with little or no gain.
Question 6. Be progressive in your training and aim to add 1kg and do 8-12 reps. If, you can't reach 8 add only 1/2kg. The trick is to be slow and sure for steady progress.
Slow Gainers Questionnaire