
Soreness is not always an indicator of an effective workout. I would suggest tracking your lifts via an app/notebook as by comparing the amount of reps/weight done week to week will allow for a more accurate representation of progress. Pick a weight that you can control, maintaining relative form throughout the entire set. Choose a rep range such as 6-10, and only add weight once you reach 10 reps.
To add to what #3 said, please do not switch up your exercises too often. The progress you see within the first few weeks of progress you see with that exercise are all from your body adapting to that specific movement pattern. Give yourself 3-4 months minimum on an exercise before you switch it out unless it is causing discomfort, pain, or you simply do not enjoy it.