I'm a very competent juggler of clubs, balls, hoops, diabolos etc etc but devilsticks scare me. They just don't look like they should work! Well done for giving them a go, though!
Not being a 'devilsticker,' the only advice I can give you would be to have a look at the
Butterfingerswebsite, click books, then devilstick, and buy any one or more of the four books on offer there. They range from £1 to £8, so probably something to suit your budget.
Otherwise, I suppose it's going to be fora of some kind, online.
Good luck...