10 common best practices and mods we should use in every circuit?

[pervyinthepark123]

I dont know if this is the kind of thing anyone cares about, but I find an input tone cap switch and variable input resistance/impedance can make worlds of difference in about anything.

[Rob Strand]

100R & 47pF = 33Mhz actually. There's a great deal of RF below that.

IMHO, for RF issues 1k +100pF is a minimum.   There is very little impact on noise and pick-up loading.
I remember a case where an amplifier used 1k + 39pF and it clearly did not work but (IIRC) 4k7 + 220pF did.
No ferrites for high-impedance ckts, use resistors.

If you want to stop squealing, oscillation etc then it's a different problem. 
Smaller caps and resistors are likely to work.

[R.G.]

I have this theory that there is a line from a country and western song for every situation.

Upon reflection, I think that for this thread, it's a line from "The Gambler".

You gotta know when to hold 'em, know when to fold 'em.