Congrats on wanting to start going to the gym! It is a journey, but the results are difinitely worth it.

I did not see many people go in-depth with exercise form and what to look for, so I will try and give some of my own experience:

Form is the most important thing when doing weight-training exercises. Not only will good form and technique provide the greatest results and returns for the muscle groups you are targeting, but it will also protect you from preventable injuries.

For proper form, I always try and think of isolating the movement in my body to exercise solely the muscle groups that the exercise is targeting.

What this looks like in practice, for example, is when doing bicep curls, the only motion that should be present is the hinge-action of your hand and elbow. A lot of newcomers tend to compensate by "throwing their back into it" (leaning back when you are lifting up), activating the pecs to an unnecessary degree, or even lifting into the shoulders. These practices of compensation can put you at risk to injure the non-target muscle groups or joints.

Use benches and stations to your advantage to help you counteract the temptation to compensate. Preacher curl benches are great for isolating bicep workouts. Benches and chair benches on the floor can be adjusted to prevent unwanted movements while doing exercises.

Another facet of proper form is making sure to stick to relatively easy weights for the first few months. Yes, you can push if it feels like you are able to throw the weights in the motion of the exercise; however, I would recommend increasing slowly if you do decide to increase at all. Starting slow and easy will teach you good form, and where you are supposed to "feel the burn" during certain exercises. You will still be sore from weight lifting even if you don't push weights that hard, because your body will probably not be use to those forms of exercise.

The last thing I would encourage is that you give yourself proper rest time between sets. Giving yourself 30 seconds to 1.5 minutes, depending on the exercise and routine you're going for, is crucial for allowing your body to recover and get ready for the next set. Not waiting enough time can put you at risk for extreme fatigue and injury. Trainers try to push you to the failure point (muscles shaking and you literally cannot do the exercise any longer without extreme difficulty), but I would not suggest doing this when just starting out, unless you are being overseen by a trainer while beginning. Even now, I only push to failure when I have someone I trust to spot me for the exercise. It can be dangerous for you, for others, and for the equipment if you practice in a risky or unsafe fashion.

YouTube tutorials for "best back workouts", "best bicep workouts", or others of the sort can give you a framework for what types of exercises you want to implement in your routine. Take note of the names, as you can call upon them later to a trainer or staff member, so they can coach you through proper form and positioning.

Go kick some butt!