I Wanna Be the Very Best
Yea that's right...I'm a Pokémon fan. Don't hate.
While I'm at it, I think I'll stick with this theme...
Since a Pokémon trainer can only carry six Pokemon at a time, I'm going to list six tools a musician needs for effective practice:
1. A quiet practice space
2. Focus / A Clear Mind
(comes a bit easier when you deal with number 1)
3. A Positive Additude
It is easy to say, "I suck, plus there are a million musicians out there who are a million times better than me. What's the point?"
If everyone thought like that, no one would practice, and there would be no progress.
Plus, you miss 100% of the Pokémon you don't catch....
4. CHALLENGING Practice Material
If what you're practicing is "effortless", then you aren't practicing. The practice room is where you're allowed to make mistake after mistake (while trying your best, of course). Get the most out of your practice by doing things that challenge you.
5. A list of goals you want to accomplish (long term and short term)
It's important to have a vision, and it is also important to maintain perspective.
6. FOOD, DUH.
My pal Totodile here has the right idea. Give your body the fuel it needs to work properly so that you can practice properly.