Well i laid my first bricks and although i viewed MANY youtube vids but still i don't think it was enough as when i got to it many things i forgot. So here are some hints.
View as many vids as possible to pick up the correct way to do things, look for vids on these subjects:
getting the first layer LEVEL.
applying the mortar to the brick
mortar thickness
mixing mortar (especially how much water to use !!)
keeping it square
keeping it straight as you go up levels
using the spirit level
using a string line
These are all good subjects to review. my personal view is find someone who has done it before it will save you alot of time, i've laid 2 levels so far and i think i will be able to do the next 7 in the same amount of time !
