This is a difficult question! I think effective use of Tiddlywiki needs education!
I mean you should learn them and it is knowledge! To be clear, assume you have bought CorelDraw or Photoshop, and because you have it, you think you should be able to draw incredible drawing/painting! THAT IS NOT TRUE AT ALL! You not only have to have an artistic taste but you also need to know the principles and basics of painting and in addition you have to know how to work well with software!
After having good knowledge of Tiddlywiki, it does not mean you are good at knowledge management!
So, I believe how to manage personal knowledge, how to effectively take notes, how to write a good article, ... are other things you need to learn!
I share some my own experiences
1. I use Tiddlywiki just like a Word document, but TW is much more flexible
2. I use a central wiki, when I open it in my browser, I see a list of wikis in the sidebar, so for example, a talk will be held next week at department on, climate change and hydrogen solution, I just have a dedicated wiki!
3. I use a few tags!
3.1 I may add/remove/modify tags later! I use Tiddler Commander to do this without hassles
3.2 I normally refine tags, I use a dataTiddler explaining a tag will be used for what! So tagging is done with care
3.3 I use Keywords field, The Kookma Solution Plugin lets you a sublevel of information
3.4 I use colors! Color if correctly used is a very powerful tool for differentiating among things
4. I use a table of content, it is always there, it helps me to have a linear TW when I need
5. I use the Kookma Favorites plugin to pin important, favorite tiddlers for quick access
5.1. I use the Kookma Favorites plugin also to freely categorize/bundle some tiddlers and see them as a folder
6. The sidebar is very useful, I use a template that lets me quickly add tiddlers to those sidebar tabs!
6.1 As an example for "
climate change and hydrogen solution" talk wiki I use (-global warming, -future energy outlook, -hydrogen as a solution, -challenge and opportunities,...), so when preparing the talk, I quickly click on a button which creates a tiddler in that section! All of these are simple and created already
6.2. Mario Link-to-Tabs (from Wikilabs) is a king here and simply lets you open the tab tiddler and modify it or duplicate and add a new tag
7. I believe search is a barrier in Tiddlywiki! So, I use fields carefully! I rarely hide things in the tiddler, fields are used for further processing and filtering, and like that, I never store data that needs to be searched in fields!
7.1. Based on the case I also use Locater from bimlas or Filedsearch from Mario (Wikilabs)
bimlas has some good discussion on using meta data and effective use of Tiddlywiki! Soren Grok Tiddlywiki is a good example of effective use of Tiddlywiki, there are other examples around! TW-Script is not a bad example but it is too wild!