I'm a professional electronics engineer (not rf enginneer though), and
what I really find frustrating about radio projects is the
uncertainty!

I spend hours designing and analysing filters. Designing oscillators
and minimising harmonics, noise etc. Then I cheerfully commit it to a
PCB (I tightly laid out surface mount PCB to minimise layout
inductances etc).

Nothing ever works as simulated. Transistors never have the rf gain
as SPICE seems to suggest.

And local oscillators...well carefully chosen components just get
thrown out the window to be replaced by more and more random changes
in component values.

If it does finally work, I'm left feeling nothing like an exacting
engineer, and more like an artist that has piles on layers and layers
of oil paint till the right effect was achieved.

I now find any mention of the 612 mixer and its (non)osclillator gives
me panic attacks. (well i'm currently trying to get it to work at
130Mhz with voltage tuning).

So I wonder, what would be your top tips for someone moving into the
radio design arena? Are there hidden secrets that nobody tells and
the books omit? I'm not thinking about PCB layout here, more things
like, are simulation programs of any use (if so which ones) and what
kind of design procedures can result in predicatable results?