Could anybody tell me the best way to line up grout lines on a wall and floor, thanks

use cross head spacers in between the tiles m8,simple as that,check the lines with your level.Some tiles especially from diy stores can be of different sizes m8,ust to warn you.

Sorry mate i never explained myself very well. I was asking that when setting up in say a bathroom, i am finding it difficult to line up the wall tile grout lines with the floor tile grout lines.

as in floor grout lines on wall follow grout lines on floor?

the tiles need to be of the same size for a start,best way is to mark a line on one wall verticallythen carry this line across the floor and then mark a line on the wall at the oposite side,hope this helps.Its all about setting out m8 good luck.

I think that you shoud perhaps avoid that.

You normally position tiles in a floor or wall according to;

1. Make your cuts easier and more practical & better on the eye or 2. to save wastage.

Now by trying to get this little detail wall grout mathing floor grout lines you may be comprimising the overall appearance of the job as well as using much more tiles than required.

Obviously when setting out you will see where all cuts etc are going to be but, I would imagine that it would be very rare for this to work out ideal e.g. all cuts coming in easy, waste minimised etc.

All the best

try to talk the customer out of it first "you need to have 3mm gaps on the floor and 1.5 on the wall or the room is out of square and the lines will run out blah blah" - if this doesnt work then set things up very carefully. here , all our walls are plasterbaord and i - 1- set things up to look nice
2-do my floor fisrt
3-do wall with mastic[no battons] and run the wall tiles down to the floor
-so it impossible to stuff it up!!