Thanks guys, I think I get the general idea again

. Materials certainly seem to have changed since I last cast a fly etc... I fished at Albury in Surrey and ended up with a lot of tangles and wind knots on the leader and was wondering whether it may have been to long at 13' or so?
It wasn't over windy but certainly affected my morale as I spent a fair bit of time untangling the birds nests!!!!! - casting technique perhaps?!
The one tool I was thinking of buying was the Orvis 'Tie-Fast Knot-Tying Tool' and wondered whether anybody had tried one or had any views on it?
Thanks for the advice so far.
By the way, I've only been twice but managed to bag a couple on each trip when others were finding it had to get a take
Derek