I usually use a "I" hook, but you can use any size. For double strand stars I use "k" or even "L" or "M" hooks.
This pattern is in American crochet terminology. Here is a good site for the differences between British and American if anyone needs it.
ch5, sl st to form a ring, or use the magic circle.
1. ch3, 2 dc, ch1, 3dc, ch1, repeat 3 times more. (5 groups 3dc, 5 ch1) sl st into top of beg ch3
sl st over to first ch1 sp.
2. ch3, 2 dc, ch1, 3dc, ch1 in same sp, in next ch1 sp, 3dc, ch1, 3dc, ch1, repeat in each ch1 sp. (5 groups of 3dc, ch1, 3dc, ch1) sl st into top of beg ch3
sl st over to next ch1 sp
3. ch3, 2 dc, ch3, 3dc, sc in next ch1 sp, in next ch1 sp 3 dc, ch3, 3dc, sc in next ch1 sp, continue around. If the 3rd row feels tight, you can add a ch1 before or after the 3dc, ch3, 3dc groups. It depends what yarn you use and how tight you crochet. This pattern is easily adjustable.
Don't forget to post your stars here for us all to see!!!!!!