How do you organize your workflow?

Hi everyone, I need your advice!

I am pretty happy to say that we`ve gathered a nice team and opened our first startup! But, we also faced a problem with organizing our workflow…

So, could you tell me, do you use any task or process management tools to organize your work? If yes, please, share with me your last experience choosing a process management tool.

I`m interested in the real impact of such tools on the work process, so I would be very grateful for your answers.