This is an idea I've been tinkering with awhile. New friends to the hobby often ask questions about what order to perform some steps, or whether or not one is even necessary for their project. To help answer I've created this little flowchart with some of the most basic steps that goes into an average build. Over all I tried to keep it as simple as possible so it's easy to understand and applies to the greater number of builders. It's okay to add or remove steps here and there if it fits your personal style or is necessary for the project you're working on. I've added comments below the chart to highlight some key talking points and related tutorials. Make sure you check them out.
The term Snap-Fit Kit is used to describe Gunpla kits which have built and assembled prior to any additional work. It lets the modeler get a better sense for the workings of the kit and make sure everything fits and works appropriately.
Relevant Guides: Construction Guide
Straight Build kits are essentially straight out of the box. I wanted to show that you don't have to go through the additional detailing or painting work in order to enjoy your Gunpla.
Relevant Guides: Posing & Display Bases
Detailed Kits represent the most common project out there. After building the kit any detail lines should be highlighted and, if you like, stickers and/or decals applied. Generally I like to apply my decals after lining the kit. If you mess up while lining there's always the possibility you might mess up the decal as well. Although decal solutions often help bind them into detail lines a bit of touch up afterwards may sometimes be required.
The Weathered Kit path is for folks who want to add a bit of girt and grime to their mobile suit. It's not necessary to have a painted kit in order to apply weathering. Though if you are painting, the weathering step would follow. Stickers aren't recommended for weathered kits as the process typical makes them stand out. Note, if painting, that most of the guides listed in the Battle Damage section will take place prior to painting. For the purpose of simplicity within the flowchart battle damage inclusive of the Customized Kit path.
Painted Kits are the second most common type of completed projects. Whether you want to keep the same colours or add your own twist the process can be fun and easy. I decided to add extra steps for priming and intermittent clear coats, steps that may not suite your build. Make sure to read the painting guides for more info on whether you should include these steps.
Customized Kits are when your imagination gets set free. Battle damage, custom weapons, pla plating, etc. Modifications is a catch all for the plethora of various workups you can do here.