How to Solve the Rubiks Cube - Step Three
This post will guide you through the Step Three in How to Solve the Rubiks Cube.
If you are here after reading the Step Two then please read along. Else CLICK HERE to goto Step One. Assuming you mastered Step Two, you should now be able to solve the First Layer of the cube. Now your cube should look something like this:
Now let's move on to the next step on How to Solve the Rubiks Cube.
STEP 3: Orientation of Last Layer
Your goal in this step is to make all the pieces on the top layer Yellow. So after this step, your cube should look something like this. 
I've broken down this step into 2 phases.
Phase 1: The Yellow Cross
If you already have a yellow cross on your cube then you can skip this phase and move to phase 2. Else hold your cube such that it matches the yellow pattern on the top (U) face of your cube to one of the yellow patterns shown on the cubes below. Then follow the corresponding sequence.
State 1: The Dot Case 
If your cube matches this case then apply the Algorithm Below and then match the result to state 2 or 3, hold the cube to match that state and do that sequence:
F U R Ui Ri Fi
State 2: The L Case 
If your cube matches this case then apply the Algorithm Below:
F U R Ui Ri Fi
State 3: The Straight Line Case 
If your cube matches this case then apply the Algorithm Below:
F R U Ri Ui Fi
Phase 2: The Yellow Top
If you already have a yellow top on your cube then you can skip this phase and move to the next Step! Else hold your cube such that it matches the yellow pattern on the top (U) face of your cube to one of the yellow patterns shown on the cubes below. Then use this same algorithm for each state. (Make sure that Yellow is still your top face and White is at the bottom).
R U Ri U R U U Ri
State 1: If No Corner Cubes are Yellow on the top (U) face, you must have Yellow Left Corner on the Left face as shown below and do the algorithm above. 
State 2: If One Corner Cube is Yellow, match your top (U) face as shown and do the algorithm above. 
State 3: If Any Two Corner Cubes are Yellow don't worry about their position. You MUST match the front (F) face with a Yellow Left Corner as shown. 
If you have carefully followed the above steps, you should be able to make the Yellow top. If you have done so, then you are ready to move to the next step.
However, if you are facing any difficulty, you can refer to my video tutorial which covers the same thing.
Got any doubts? Ask it in the comments section down below.