It depends on the type of paint. I use a grease dissolving dishwahsing liquid as a pre-soak before I wash a paint stained garment. I spurt it on both sides of garment, rub with a nail brush, reapply, let it sit for 10 minutes then launder as usual.
Use clean cloth dipped in white spirit, then use carpet or upholstery shampoo.
Test on a hidden area first as the white spirit may cause discolouration.
Remove as much dried paint as possible. Then, use neat washing up liquid on stain, then sponge repeatedly with cold water until the water is clear. Use shampoo if necessary.
As the paint is water based there is no need to use anything other than water to remove.
This works to remove paint stains from a sink.
Pour boiling water onto the paint, leave for 30 seconds or so, then scrape with a plastic scraper to avod scratches... if it's really bad fill the sink up with boiling water leave for 5 or 10 minutes then empty water and scrape with plastic scraper. If this doesn't work put turps onto a cloth and rub at the paint, be careful if it isn't a steel sink, because you don't want to wreck the varnish topcoat.
When this has happened to me in the past I have always used the very thing that cleans the paint brushes...either white spirit or turps. I have even used nail polish remover on some really thick stubborn marks. You don't say what type of fabric it is... but just to be cautious I would do a test on an inconspicuous area of the fabric to make sure that it does not strip the color from the fabric. Always use a clean white cloth or cotton wool so you can see if the color is coming out of the garment.