Well...using a mouse is really difficult to do dude. That's why I use a art tablet. X3

im too poor to buy one

If money is the problem, May I suggest trying Vector art ? (Programs like Illustrator, Flash,Gravid Designer and Inkscape) I do vector art and end up using Mouse like...90% of the time.No fancy hardware required, I've done drawing only using my phone camera and usb mouse. or if you don't fancy vector art you can learn to use the Pen tool in photoshop just as good. Let me know if you wish to know more.

im sorry i dont understand

The program you're using does bitmap art where it draws each pixel which can make it wobbly but in vector art it calculates the stroke you did to make a smooth line. Also if you have an ipad or an Android tablet you can get a stylus and use either an art app or an app that can connect to your computer allowing you to use it as a drawing tablet but it's recommended to use an actual drawing tablet because ipads and such can be delayed and laggy.

*brain making dial-up sounds*

Just watch an Adobe animate tutorial or something they usually say what vector art is.

i thik i'll stick to sai.
and i cant afford a tablet

Best of luck to you, hopefully you will be able to obtain an art tablet soon.