Garden walls using hollow blocks, any tips?

[edthedead]

The time has finally come to replace some old wooden retainers in the garden I put in as a temporary measure about 10 years ago!

The tallest point is about 0.6m but the majority of the walls will only be one or two blocks high. I'm planning on using 5cm of mot 1 compacted then 15cm of concrete on top for the foundation (twice the width of the blocks) onto fairly sandy soil, lay the blocks then render and top with coping stones. The blocks will be filled with concrete. Sounds easy....

I've never layed blocks or bricks before, any tips or comments from those more experienced than me?

[sfella]

Build the ends up witha spirit level to how ever many courses your going then use a string line between the two ends to lay the middle to. It needs to be a builders line not a piece of normal string, it will pull nice and tight without snapping and wont be sagging etc. Make up a decent amount of mortar so once started you can keep going. A few old pieces of board as spots dotted along the length are easier than working put of a barrow. Mix up quite stiff, you can't lay blocks with something resembling slurry! Then just keep checking with a straight edge/spirit level that your not bowing out or leaning etc. As they are hollow you could fill them if you wanted with concrete for extra rigidity.