Rock Band 3

For any of the road challenges just play within your comfort level of difficulty. I would say anything above Medium will suffice. Some tips on specific "types" of spade achievements:
*Hit full overdrive as much as possible: some times I would purposely miss more overdrive phrases while my current drive was running as to not keep it going and wasting more future phrases.
*Overdrive Overdose: every time you hit 50% on the overdrive bar, hit it.
*Overdrive Chain: get your overdrive up to about 75%, wait 10 seconds, then hit it so that you will probably be coming up on another 1 or 2 overdrive phrases that will keep your overdrive going longer.
*Overdrive Streak: same concept as the Chain with regards to maintaining a long overdrive period...but you also need to streak your notes the whole time during it. No misses!
*Streakmania: there are a few different types of streaks but basically just try to maintain your streaks as much as possible.
*All for One: If you miss a note or two just do your best to not worry about them and get back on track.

You need 90 spades over the course of 5 setlists. The setlists choice vary depending on what you have or haven't got in your downloadable song list. But the first choice always remains the same.
Of 12 songs you need on average 7-8 spades a song, every star counts as a spade, Gold Stars still count as only five spades. When you start a setlist you are given a task which will allow you to get more spades. It could be accuracy, streak or something to do with overdrive. Nevertheless it will show up at the start of the setlist and remind you before every song. Always focus on trying to get the five spades first, the stars will take care of itself. If you've got the five spades, then focus on your score which affects the stars. If you are still struggling on getting it, restart the song and go down a difficulty. You can even do this on easy!

It should be noted that for custom setlists, you can press the back button, which will bring up the sorting options, and reset the settings (Yellow Fret/ Pad or Y button) so you can pick easy songs for the challenges. Personally, I'd recommend Walking on the Sun, Charlene (I'm Right Behind You), which is a free DLC song, and Imagine, which are all very easy on bass, especially the latter two as the majority of the notes are sustains, even on Expert. All of these songs could easily be Gold Starred by a novice, so even if you aren't that good at guitar, as long as you have one, this is the easiest way to get the achievement.