((This post got longer than expected. My advice in a nutshell: Don't worry about speaking yet. Do it when you can but focus on input for now.))

Don't "arrange" speaking practice in the earlier stages! Use what you know and try to talk when you're with people who 1) know Japanese well and 2) are tolerant of being used for practice..?

I'm on the radical side of things but I'm big on not pushing output. You want to get your muscles used to making these sounds, it's true, but that can easily be done by reading out loud/shadowing/etc etc.
Once you've gotten used to the language as it exists normally- output becomes fairly easy.
I'm a dirty, rotten perfectionist so I was always holding back from speaking until I was ready to be good at it and I seem to have turned out alright (next-to-no output for ~2 years in the beginning. it wasn't until I was reading novels without a dictionary that I was beginning to have conversations).

Having speaking partners is nice. But you don't really learn or benefit that much from output until you can output enough to sustain a conversation (and so receive input you can understand). New knowledge *can* be gained from your partner but you will almost always get more benefit from pure input.

It kind of sucks- I won't lie- because obviously you're learning the language to communicate. But I'm just not sure how beneficial it is to push output before you have enough of the language under your linguistic belt!

PrettyInScarlet wrote:

The thing is that both of them have never taught anyone before so I would like to prepare some draft plan for our future lessons and discuss it. My speaking skills are close to zero and I don't have any idea how to arrange these sessions  but I would like to use my precious time efficiently.

It's kind of a long video, but in the Fi3M interview with Tim Ferriss he talks about how he structures one-on-one conversation sessions with people who aren't teachers. It's definitely worth watching all the way through, but I think the part about conversation practice is near the end. It sounds like that's sort of what you're looking for.
http://www.fluentin3months.com/4-hour/

Realism wrote:

Listen to native-spoken Japanese A LOT

Just try to repeat everything you hear

Try to read out everything you read, but read it out loud in a natural way, do not speak out loud and read every word slowly, that's not gonna help.

Ok, here's a thing you can do to really improve your speaking:

Listen to a Japanese rap song and rap along to it. Trust me, this will help TONS.

Thanks for posting this. I just got to the conversation section at about 20 minutes in.