There are a couple of things that you need to know before you start laying your bricks.

Gauging Your Brickwork
First, you should plan out the dimensions of the finished product, taking into account the dimensions of the bricks you’re using and the required thickness of the mortar joints (how thick the mortar needs to be between the bricks). This is called brickwork gauge.

A typical (load-bearing) mortar joint should be 3/4 in (10 mm) thick—for both horizontal and vertical joints). For most other applications, as long as it is between 1/4–1/2 in (7–13 mm), you should be fine.

In some countries like UK, a brick is typically 65 mm in height X 215 mm long X 102.5 mm deep (sometimes, they do vary though). With typical mortar joints, that makes the average brick coordinating size 75 mm in height X 225 mm long X 102.5 mm deep. Obviously, two courses (stacks) of bricks would be 150 mm high, and four courses would be 300 mm high.

You should only make these measurements after you have your first course in place. (You will measure from the top of your first course.)

Checking the Weather Forecast
Second, check what the weather will be like for the next few days. Don’t lay bricks in the rain or cold/freezing temperatures. Any rain that gets into the mortar before it sets will make it run down and stain your brickwork, or worse, destroying the structure you just built.

Cold weather will also delay the setting process. Any frost will also get into your mortar and cause it to crack (especially if you didn’t use any additives). On the building sites I’ve worked at, it has to be 36 ºF (2 ºC) and rising for bricklayers to be allowed to start.

How to Lay Bricks
The steps I’m about to show you are applicable for almost all bricklaying projects. I’m going to use my very first project I built in college as an example: building a simple brick pyramid (10 total bricks).

The bottom course is 4 bricks long.
The second course is 3 bricks long.
The third course is 2 bricks long.
The final course is just 1 brick.
This project should take between 30–60 mins, depending on the weather conditions and how absorbent the bricks are.

1. Spread the Mortar
Spreading mortar is quite difficult at first and will take some practice.

Only pick up as much on your trowel or as you are comfortable with. The more you practice, the more you’ll be able to pick up at one time.
Spread a generous layer of mortar along the area you intend to lay your bricks.
Trim off any excess mortar from the sides of your spread (you want it to be only slightly wider than the depth of your bricks), and use that excess to extend your spread further down.
2. Create a Trench in the Mortar
Angle your brick trowel so that the tip is pointing downwards at a 45-degree angle, and make a trench or “bed” in the mortar by pressing the trowel into the mortar as you move down the spread. This makes sure the mortar will contact the entire surface of the bricks.
Again, trim off any excess mortar on the sides.
3. Lay Down the First Course of Bricks
Pick up your brick. Make sure you have a comfortable grip
Lay the first brick onto one end of the spread.
Push it down evenly until you get the desired joint width.
Add mortar to the end of the brick to create a vertical joint.
Position the next brick so that you have a uniform mortar joint.
4. Check That the First Course Is Level and Straight
After you have laid four bricks, pop your level on top. You want the bubble to be perfectly central.
Gently tap the bricks that are not level until you have a level first course.
Also check that the bricks are lined up with each other. Use your line and pins to make a line that’s flush with one of the bricks at either end.
Gently reposition any bricks that aren’t flush with the line. Be careful not to tap down as you’ve already levelled them.
5. Lay Down the Next Courses of Bricks
Continue laying down the second, third, and final courses of bricks using the same techniques above.
Make sure to stagger the bricks. The vertical joints should line up with the middle of the bricks above it. This is called a half bond.
Level your brick on top just like you did before.
6. Check That the Brickwork Is Plumb
To make sure your structure is level vertically, place the level along the face of the pyramid and make sure the bubble is in the middle.
Plumb the two end bricks and place your level across vertically across the 3 so that you can ‘range them in’. There should be no gaps between the brick and the level.

Source: Dengarden