I have never layed much brick, but have layed enough block , and a lot of stone,
once one builds the corners, some use a story pole, a stick with the level of each course, and use a level to get the end course vertical and level,
then set a string when the corners set up, the trick is not to touch the string in the setting of the block or brick, if you do you will end up bowing out the wall, use a level in the setting process to keep the block/brick, level across, (I liked a torpedo level, I keep a sting on the level as fishing out out of a block wall is many times not possible).
mix the mortar up, and get ti tempered, it may take a little experimenting, to get the water mix correct, to soupy and it will not support the block and to stiff very hard to set the block, it is close to correct when one can take a bit of mortar on a trowel and throw it against a block or brick wall and it will stick and stay or a lot of it will.
If your trowel is to large it is difficult to use and handle with mud on it, and to small you will not be able to have enough mud to prep the block or brick for setting.
on the tuck pointing , one can use a grinder with a diamond blade on it to clean it up some more, take a tuck point trowel and and hawk or brick trowel and set the hawk/trowel up to the joint and use the trowel to fill the joint, and then use a jointer to finish it off,
Brick
YouTube - The Art of Laying Brick
IMO you want to butter both sides of end of the brick,
block
YouTube - Brick Laying and Masonry www.masonryworktools.com