You've looked at yourself in the mirror and decided that no, you're not fat. There just seems to be a bit of a belly and some flabby arms that won't go away. You know that you need to do some resistance training for your belly and arms but how can you ever fit it in? You do it at home!
First, what I am about to tell you will only work on flabby arms and a pokey belly when used with a total approach to getting in shape. That means proper diet, cardio and resistance training as a system.
Lets talk about the flabby arms first. The easiest thing you can do to tighten up flabby arms and a droopy chest is the press up. I know you may have difficulty with them but that's because they are hard, but they also work VERY well. We will call the press up a pushup from now on just because that is the term that most people use. The pushup has many variations and I am sure that one of the ones I give you will be well within your ability to do until you get to the full military pushup variation and beyond.
You want to keep your core tight. What you do not want to happen is that when you push up, you look like you are peeling yourself off the floor. I call this worming. A lot of people do it when they get tired. First you will see them raise their heads, then their chest and finally their hips leave the floor. What should happen is that you contract your core so that everything from the base contact point (feet or knees) is lifted off at the same moment.
The first and easiest version of the pushup is the wall pushup. This is simply standing face into a wall and doing your pushups by pushing against the wall until you are standing straight. You lower and push over and over. If you can do 15 to 20 reps of these two to three times then it is time to go onto the second version.
The second version on the scale of difficulty in pushups is the box pushup. Instead of pushing against the wall, you will push against something that is 1-2 feet off the floor. You should probably do these with your base being your knees instead of your feet like in the full military pushup. The couch will work and so will the coffee table. Make sure you position yourself so that when you touch the couch (or whatever) in the bottom position your lower chest is the contact point. Aim for the nipples if you want an exact spot. After you can do 3 sets of 15 on this version, you are ready for the next step in your pushup evolution!
The third version on the scale of difficulty in pushups is when the pushup is done on the knees. Everything about this version is the same as the regular full pushup except that your knees do not leave the ground. This cuts out the extra weight from the knees to the toes making the pushup a little easier than the full version. Again, when you get 3 sets of 15 repetitions, you are ready to move on.
The fourth version in your journey to a full pushup is the knee pushup with a full pushup negative. Now we are getting somewhere! The trick with this version is to do your pushup as in the above version and lower yourself in the regular full pushup version. The reason you do this is because you are always stronger in the negative or lowering portion of the movement than in the positive or raising portion. So we do the heavy full pushup negative and the easier knee pushups to raise your self up. When you feel comfortable with the movement, try this to tighten up the flabby arms.