There are lots of things to take in consideration when starting a template from scratch: materials, favorites, pen sets, graphical overrides, layers, layer combinations and view/publish layouts are the most important ones. You also need a good work environment (the way your menus & toolbars are set up, as well as shortcuts and other settings) before you start your template.
The best place to start is probably Shoegnome, run by Jared. Check out Jared's templates and work environments: Shoegnome
Archicad offers some sample projects, although I think they are a little outdated / too standart in some cases. Have a look at them anyhow: AC Sample Projects
Fellow forum user Podolsky recently shared his own template / pdf manual. Although being a little more advanced, it gives a great idea of the level of customization you can end up with: Forum Thread
Then, if you are interested in something even more complex, you could check out ContraBIM's products. These are however paid templates: Contrabim. If you are not willing to pay just yet, I would highly suggest checking out their youtube channel anyways, as John shares a lot of useful information about AC in general but also creating templates.
Creating a template can seem like an overwhelming task to get started with. And in some ways it is, seeing as there are so many elements you have to 'decide' without having a specific project. Just start small, with the stuff you know. Then use it on a project, and modify it. It's okay to set up %50 of it in the first try, try it on a few dummy projects, take it up to %80-90, and then fill out the remaining %10 over the years as you work on real projects. Don't worry about getting it perfect the first time, this is impossible as templates will evolve and change over time according to your needs. I've also found that creating an accompanying excel sheet for layers, shortcuts and some other parameters has helped me greatly in keeping things organised. This also has the benefit of being able to educate my colleagues in a faster and clearer way. Good luck!
*edit: oops looks like Laszlo beat me to it
leaving my comment anyhow since it contains other information too.
The best place to start is probably Shoegnome, run by Jared. Check out Jared's templates and work environments: Shoegnome
Archicad offers some sample projects, although I think they are a little outdated / too standart in some cases. Have a look at them anyhow: AC Sample Projects
Fellow forum user Podolsky recently shared his own template / pdf manual. Although being a little more advanced, it gives a great idea of the level of customization you can end up with: Forum Thread
Then, if you are interested in something even more complex, you could check out ContraBIM's products. These are however paid templates: Contrabim. If you are not willing to pay just yet, I would highly suggest checking out their youtube channel anyways, as John shares a lot of useful information about AC in general but also creating templates.
Creating a template can seem like an overwhelming task to get started with. And in some ways it is, seeing as there are so many elements you have to 'decide' without having a specific project. Just start small, with the stuff you know. Then use it on a project, and modify it. It's okay to set up %50 of it in the first try, try it on a few dummy projects, take it up to %80-90, and then fill out the remaining %10 over the years as you work on real projects. Don't worry about getting it perfect the first time, this is impossible as templates will evolve and change over time according to your needs. I've also found that creating an accompanying excel sheet for layers, shortcuts and some other parameters has helped me greatly in keeping things organised. This also has the benefit of being able to educate my colleagues in a faster and clearer way. Good luck!
*edit: oops looks like Laszlo beat me to it
leaving my comment anyhow since it contains other information too.
