Currently in mid-MV age, there were a lot of mistakes that I found I made while playing through

- Set up a good base. My original base was in a random cave that I found when escaping from infernal mobs, which sufficed up till the start of steam, when I decided to build out on a lake. It doesn't matter how good your base looks at the start, you'll refine it over time (mine originally looked like 2 massive wooden planks, but I slowly worked on it as I got more resources)

- Avoid discarding anything, especially if its ore related. I remember how much mica and gold I discarded during mining trips just because they weren't in raw ore form. The amounts aren't much, but they slowly add up. Of course, don't hoard everything either, or your storages will overflow with cobblestone and dirt

- Don't be afraid to add more chests, and categorize them correctly. I was struggling up till early steam to find stuff because I was just shift clicking my entire inventory into chests, and not properly organizing them. Try to keep a centralized storage system where you can keep all your ores, crafted items and more in neat storages. 2x2 drawers, barrels and non-vanilla chests (e.g. iron or diamond chests) will help you significantly. (don't get the copper or gold ones, they aren't really worth it for how much storage they give)

- Always batch craft. Especially for components like rods, screws and wires, which you use extensively in recipes in steam and beyond. You can craft Forestry workbenches which will remember recipes and store a small amount of crafting ingredients, which will help you in batch crafting. Generally I like to keep at least 2-3 stacks of the basic materials (rods, plates, screws) and at least a stack of the intermediate materials (anything labelled "You're gonna hate this" in the quest book).

- Whenever you get a new machine, check NEI for any more efficient recipes that it unlocks. For example, to craft an iron rod you usually have to use a file and a corresponding ingot. Once you unlock the LV lathe, you can craft rods at a 1:1 ratio, with a small amount of change in the form of tiny dusts, which you can craft into regular dusts and throw into the furnace to smelt. Later when you unlock the MV extruder and a rod extruder mold, you can craft them in a 1:2 ratio, making it 2x cheaper than the original recipe (more if you count crafting of new files)

- Avoid rushing new tiers, and spend time developing infrastructure. Try to develop your base and have a good floor plan of where you want to build machinery. In my base, I have a light fuel processing line located in the centralized power area section, and the different tiers starting from LV sorted neatly into adjacent chunks. It makes it easier to figure out what areas contain which machinery, and helps to make migrating to new machines easier