First off, of all the techniques listed in the "answer", only one ("plinking") is actually about linking normals. The rest are all cancelling of some sort.
Plinking is an advanced technique, but if you are having trouble linking normals, I wouldn't recommend learning to plink just yet. Plinking is particularly useful for advanced players who are interested in improving their execution on combos which involve one frame links--one frame links are very difficult to execute on a consistent basis, even for pros. That being said, most characters in the game do not need one frame links to execute bread and butter combos.
Here is my recommendation: practice. I know it sounds like the obvious answer, but there is no shortcut to being a good at Street Fighter (or any fighting game for that matter). Practice is important because it builds muscle memory that will help you link moves on a consistent basis.
Go into practice mode and practice the specific links that you find difficult. That means don't attempt to learn an entire combo all at once, but learn each of the individual links first, before you put everything together in a full combo.
Use failed attempts to help you get better. You can set the practice dummy to block anything after the first hit--that is, block any move that you did not successfully link. Practice the links and pay attention to how your character and the dummy react. If you attempt the link, but the second move never comes out, that means that you performed the second move too early. Take this into account, and try delaying the second move a little more. If you were able to perform the move, but the practice dummy blocks it, that means that you performed the move too late. These steps will help you narrow in on the right timing.
A useful tip to help narrow in a little further is to pay attention to the animation frames or voice of your character during links. Hopefully you can landmark the right moment to execute the second move.
After all is said and done, if you still have a hard time linking and you feel like giving up on Street Fighter, try out a character with target combos! Target combos are very easy to execute because they don't require links.