You can always start out your SMT designs with DIY laser-cut stencils but eventually you’ll want to upgrade to a stenciling machine. Stencil machines hold the metal-cut stencil flat and taut so that you dont have any shifting or curling while you try to lay paste down. The good ones have a fixture so you can always get the same alignement every time – speeding up your stenciling time down to under a minute per PCB. They’re a little expensive, but if you ever plan to do over 100 of a PCB they are essential!
Here is a brief review of the stenciling machine we use here at the adafruit shop. Its a manual machine and uses framed stencils but we liked it for its simple fixturing setup that allows double-sided boards, enjoy!