There is a huge variety of choices when it comes to building models. Models come in such a variety of sizes and materials it may be difficult to know where to begin. At first when you are a kid there are the snap together models of cars and planes that come in a box and you put them together and cover them with stickers. It all takes you an hour or so. The model may find its way onto a shelf, hang from a string or get played with and broken all in the same day. As one gets older you may start putting together one of the slightly more expensive models that must be glued together. These models also tend to be covered with stickers. When a model builder gets into the art of model building more, he/she may get into doing their own paint jobs on a model car. At this point there is a big choice to make, or maybe a specific preference develops. Are you one that wants to build models that you can drive or fly, or will you focus on the delicate work of model making. For some, focusing on the delicate work of model making can lead to creating whole scenes, not just individual models. For those that prefer models that run on small electric or gasoline engines the focus is on mobility. These models that need to take into account aerodynamics and real life movement, the vehicles can take on a different look than just a miniature of a human occupied vehicle.
There are model building projects from everything such as cars and airplanes, to boats and buildings. People build diaramas that incorporate many types of models. Regardless of the item that you choose to assemble model of, it is probably best to start with a kit and follow the specifications. As you become more advanced you will find making modifications will be what excites you.