The following is a write up of how I made my own mini canister filter. I do not have photos of the actual process of doing it as this whole filter was done in only a matter of minutes. I will however give a run down of what I did. I hope the photos provided throughout this project article will give you a good enough idea of how to proceed in the listed steps below.
 

First off, these are the main items that are required for this DIY canister filter project:

1. Container
Obviously them most essential item in our list. The most important consideration is that it be made of plastic so that making holes in it would be easier, without the need for specialized tools. Both the container and its cover have to be made of plastic as we will need to make a hole to function as an inlet on the container proper, as well as another hole to function as the outlet on the container's cover. It would be more ideal to use a black opaque or translucent container as beneficial bacteria thrives in a darker environment but for the purposes of my project I opted for a clear container as it was easily available.

2. Pump
Since this mini DIY canister filter will be employed for use in a freshwater shrimp only tank, I do not need to make use of a very powerful pump. A pump which is strong enough to pump out water from the top of the container is all that is needed. I ended up choosing a cheap submersible pump which only outputs 150liters/hour.

3. Hose & pipes
These should only be purchased after the pump has been purchased. Reason being you need the hose to fit the pump output pipe nicely and firmly. For the inlet which is formed by a long tube and L-joint, I suggest buying both of them together from the shop so that you are sure they can fit nicely. For me, I salvaged the tube from an old HOT (hang on top) filter, and the L-joint from my other spare parts. Luckily for me, they formed a snug fit upon fitting the tube into the L-joint.

4. Media
This should be the easiest to obtain for most of us. I intend to place some ceramic rings at the bottom, followed by a layer of Eheim Efhisubstrat on top. I do not intend to place cotton in the filter since space is a premium inside (Actual fact is I am too lazy to open the canister and wash it everytime :p )

5. Others
Drill with various drill bits - The main tool for making the holes in the container and its cover
Pen-knife - For cutting here and there
Round file - To file off the rough edges after the drilling
Silicon - To seal any possible leaks ( if required )
Water & dish washing liquid - You will find out its use in the 'Tips & Tricks' part of this article.