this is really my first time making something in Blender without a tutorial. I am trying to make this robot arm, but I am unsure about the proper method to do so. I have outlined the object I am trying to create in red and my current attempt is also attached. I have used a boolean modifier to create the circular shape for the shoulder of the arm but it has far too many vertices which lead to too many edge loops lower on the arm. The arm becomes smaller lower down and the topology gets messy because of the extreme number of edge loops. I want to ensure that I am practicing proper technique and creating good topology. Should my circle have less vertices? Or is there a good way to reduce the number of edge loops as the arm goes down further? If I am using any terms incorrectly you can also feel free to correct me. Thank you so much!
Less is more ...
Add Circle 8 sides (Rotate R 22.5, Extrude E, Scale S, Copy Shift+D, move and scale down, select 4 vertices press F ...
Add Subdivision Surface Modifier
Select edges you want keep as Sharp Edges Shift+E press 1
... here topology version for Quad Evangelists :)
Add thickness - you can simply select all and Extrude or use Solidify Mofifier. For more natural look of edges try Bevel Modifier
in some cases you can also use Bezier Curve with very similar workflow of creation - start from circle, duplicate, scale, extrude or connect points. You dont even have to manipulate with handles, you just select few of them and switch handle type V to Vector that automatically switch direction to point of a next control point.
For extrusion and bevelling edge use Properties Editor > Object Data > Geometry > Extrude and Bevel > Depth. But keep in mind model can't be unwrapped, but it doen't has to be a deal in some cases with pointiness and other procedural material nodes.
Though there is already an answer detailing the "proper" way to deal with mesh topology, I will present a different alternative using curves.
Add a curve>Circle.
Enter edit mode select all the control points, duplicate and move.
Duplicate and resize.
Select two control points and subdivide.
Move the new control point.
Subdivide more points, move and rotate until you have the shape you need.
Exit edit mode, make the curve a 2D curve and set the fill to Both (so that it is filled top and bottom)
Give it some extrusion and bevel.