A goal without plan is just a wish.
-Antoine de Saint-Exupery
A pipeline or workflow is an essential aspect to make sure that your game development process goes through smoothly. This is why making sure you have a good one is very important. Especially if you are working alone Working solo means you are in charge of everything. One mistake I did with a previous project was to just work on what is required at that time of development and it wasted a lot of energy and time in the end In my project there is only 3 essential section of the pipeline:
.Art .Programming .Design
Design is the important process of basically coming up with the blueprint of your game. Here is the part where you brainstorm ideas. All your game mechanics and storyline comes here And it's great to have an idea but you need to be realistic to make it a reality. When designing you need to think questions such as "How will I accomplish this?" or "Is this really important?"
Remember, you are working solo. This means that time that you have for your project is precious. Hence, you need to save as much tine as possible and that comes from the design process. This is achieved through skipping producing content that is not essential to the game. It is nice to have a lot of unique features in your game but there really is no point to work on them if people are not going to be using them that much
Look at Call of Duty's legendary "Press X to pay respect" You can't choose to say no. It won't make a difference to the story and to think that someone actually had to go through the trouble of programming that and making all the texts for it, it's kinda sad. That sequence could have worked just as well if it was just a cut-scene with Mitchell putting his hand on the coffin without that Press X bit.
It may not be much but if you have a lot of "Not much"s, eventually that will snowball into one "Quite much" problem you would want to avoid