@Madhuparna04 Where in aima do you want to submit it?
I work on game developer tutorials and my impression is that lots of game developers would be interested in your tutorial if it were on your own site, or github, or gamedev.net, or reddit, or some other site, but almost none of them would look at it if it were on aima
I think up-for-grabs is for when you're looking for open source projects that need help. Useful when you're going the gsoc route. There's a popular list of some 72 freelance websites that you can check out by googling. I get most of my clients from LinkedIn and alumni base of my university. Once you get one or two clients who have rich people in their network and you perform good enough you start getting clients easily.
Sometimes its more about how you interact with your client and less about the code. Non tech people usually think these things are difficult, so one way I know to impress them is give them updates through screencasts with OBS studio instead of video meeting regularly. It tells them that this guy's serious and will do the job without slacking off. I've been told by several people now to start a youtube channel because of these video updates.
I also scrape any of those freelancing websites sometimes to get details of the companies / recruiter that wants some service and I just call them to see what's the deal. Get very interesting responses and also helps build network. Make sure you have a portfolio website though. In most places they want to see portfolio or resume as a website as well as a PDF (given you're going for a UI job) but do it anyways, it has an impact on CEOs and recruiters.
It made me think, not just as a programmer, but as a designer and as an educator, asking how to best show or teach something using my ability and not simply just to write code.