The Art of CAD: Art

Troubleshooting

use Tools>Sketch Tools>Check Sketch for Feature
can use SketchXpert to help solve overdefined sketches (click on Over Defined button)
to check if something is a planar face, click on face. If it is planar, the sketch tools will enable.
understand limitations. For "up to next" the face needs to have a complete "next" to go to. If it goes outside the body it won't work.
complex fillets occur when there are more than three edges meeting in a vertex, or when they are of mixed convexity. Fillet what you can, chop out the bad part and apply a blended patch
you can Rollback to move among time-dependent features in an assembly
you can pick on a face and RMB>View Mates. You can also just view the errors (RMB>View Mate Errors).
use File>Find References to make sure the files are being pulled from where you think they're coming from
use Find References
turn on T>O>S>Feature Manager>Arrow Key Navigation to scroll through . Focus on rollback back and use up-down arrows to visually follow construction.
flex your components

if a shell cannot reorder features, check the parent child-relationships
feature order is important. adding draft can cause problems with fillets. do draft first, then add fillet later.
if possible don't import wireframe geometry since they use a significant amount of system resources
use Tools>Check to find import errors, or Tools>Import Diagnostics to find and repair errors.
use MateXpert (MateGroup>RMB>MateXpert) to diagnose assembly build problems
use FeatureXpert to solve problems when fillets and draft features fail
Use FilletXpert (under Fillet) to create multiple fillets quickly. Use change, remove to remove fillets you did not want to keep. It uses FeaturesXpert and Reorder to help resolve problems.
do a draft analysis to make sure your faces are drafted properly
complex blends (K,T,X,Y intersections) are not done with fillets.
use Tools>Feature Statistics to see how long it takes to build your part. You can see what features take a long time to rebuild and edit/suppress to improve efficiency.

you can temporarily or permanently deactivate all external references. Lock All allows you to unlock the references later. Break All permanently gets rid of the external references.
you can Lock All external references to temporarily stop having a part be updated. This may help with workflow.
when diagnosing mate problems, best to start at bottom and work your way up
best practice: fix errors as they occur
don't use break all references. Can lock all instead, and then can unlock later. Instead of break use edit. break your references from bottom to top.
use FeatureWorks to repair imported parts. Usually works better on prismatic parts.
only mate to Time Dependent Features (assembly features, geometries, in context features, component patterns) when it is the only way to achieve design intent.
sometimes loft gives you an approximate surface, but avoid degenerate surfaces. Model surface in a different way (e.g. Filled Surface).