Anglesey County Council publish a series of pamphlets entitled "Circular Coastal Walks on the Isle of Anglsey", which I have found to be very useful and detailed. They each cover certain areas (some have 2 or 3 walks from the same start point) and are mostly waymarked. They cover areas such as Llandona, Pentraeth, Brynsiencyn, Llyn Alaw, Amlwch, Moelfre, Dwynwen, Newborough, Aberfraw, Holy Island etc. and there was also a separate 42 page booklet (with maps) available last year entitled "Circular walks on Anglesey's coast".
They are available from libraries, tourist information etc. and probably also on-line. I got at least 9 pamphlets and the booklet from the Tourist Info. at Llanfair P.G. and they have been very handy.