Your number one priority when you engage in strength training is to improve muscular strength through all major muscle groups. This means overtime you should increase strength in the basic exercises.
Pullup, pulldown, or row
Walking lunges or leg press
These are the basic exercises that engage the major muscle groups of the body safely.
If you are an athlete focus on doubling your strength in these movements over the next six months.
If you double your strength your athletic performance will improve whether that be run faster, jump higher, or throw a ball harder. Of course, assuming you are doing some sport-specific training that includes biomechanical training of technique and form.
In the weight room, your focus must be on getting stronger on these basic exercises.
For athletes, your goal should be to do 20 pullups with your bodyweight and chest press your body weight for at least 10 reps and advanced athletes will need greater strength.
For walking lunges your goal should be to hold your body weight in your hands and complete 6-10 reps per leg. For example, if you weigh 150 lbs you will need to work at holding 75 lb dumbbells in each hand while performing a lunge.
Get to these strength levels and then we can talk about performing other exercises or focusing on other things.
Be intentional when it comes to strength training!