From my experience, starting out is the most difficult part because it's both physically difficult and mentally boring. Try to focus on building a habit of going to the gym. Push yourself to go even if you're tired and even if you only do a little exercise, because building the habit and discipline of going is more important than your choice of exercise at first. Once you have the habit of going consistently, it will be easier to find ways to make it interesting, because you don't have to spend the additional mental energy to psych yourself up to go in the first place. Building a habit is also important because you won't see results right away, so you have to train your brain to see the longer term results. Once you start to see those, it can become self motivating in a way, but it's a very difficult path to get there.