I have been working out at the gym a few days a week, purely cardio.

But now I'm wanting to start lifting. But I have no idea where to start. I signed up for an initial training session (you know, the freebie that most gyms give away!) and I was pretty disappointd. They taught me how to do it, but not how to tell what weights to start out at.

How do I find the right weight for me?

Finding the right weight for you is pretty much trial and error. It's going to be different for every machine and every exercise you do - that's why it's really helpful to carry a notebook around with you in the beginning to keep track of your weights.

Generally speaking, when you are starting out, you want to be in the 12 - 15 rep range. That means you want to be lifting a weight that becomes challenging or almost impossible to do another rep somewhere between 12 and 15 reps. If you get to 15 and you can keep going, you know to pick a higher weight for the next set. If you can barely crank out 8 reps, you know to go lower the next time.

Just as a guideline, when I do an orientation in the gym, I typically would start with these weights - you could try starting here and see how you do:

Lat pulldowns - 30#
Seated row - 30#
Pec flye machine - 15#
Chest press machine - 30#
Shoulder press machine - 20#
Bicep curl machine - 20#
Arm extension machine - 20#
Cable pushdowns - 20#
DB curls - 8s
Kickbacks and other tri exercises w/DBs - 5s
DB shoulder exercises - 5s

Have fun lifting - you're going to the results!!

One thing to consider before taking up external weight like dumbbells or machines, it to simply use your bodyweight. Don't underestimate the workout you can give yourself simply by doing exercises such as bodyweight squats, pushups (wall pushups is a good exercise to start at if you've never really done them), lunges, step ups, chair or table dips, hip/thigh extension, etc.

there are many variations and levels of difficulties of bodyweight exercises that you can use before ever needing to touch a dumbbell or machine and it's a great way to get your body into a better conditioned state before "graduating" to using external weight.

Michael Navin, CSCS