I gave Seren the cup empty and let her play with it, then after a week I put water in it. She now takes a bit, mainly through chewing down on the spout (ts one of those ones where the baby has to bite down to get water out).
Weestar you are advised not to give juice in a bottle as it causes the juice to pool around the teeth and can cause decay. You can get tooth friendly beakers (you should also try to limit use of those beakers where the baby has to really suck the juice out as this does the same thing as bottles) from Boots etc