What method do you use? I used to use a dotting tool dipped in water to stick my rhinestones on, but it became a hassle with the constant dipping of water! I have found another way to stick them on and funnily enough, I saw it on eBay :)
*Update* You can also use a toothpick with blu-tack on the end!
Marbling takes practice and knowing some key techniques is helpful in achieving a successful result. When I tried marbling, I didn't know much and didn't end up getting great results. Here are some tips that have helped me make water marbling much easier!
Hope this was helpful!