I have tried to add tags before, but I do not feel moved to do it most of the time. The categories that I created for French, for example, all seem meaningless to me now. The only tag I remember creating for Japanese is うwhich tells me there is an elongated "o" sound in the word. But I rarely remember to use this tag.

Any hints on how to get into tagging and some suggestions for useful tags in a given language?

I sometimes tag for particular patterns, blocks of sentences that I could slot other words into, and have ready-made, grammatically correct examples. Always relating to bits of the language that are very different from english, and so, bits that I really need to work hard at internalising.

With Russian, pretty much everything (nouns, adjectives, pronouns) declines all the time; across gender and plurality, depending on case. 7 cases which can be triggered either by prepostions or verbs. So I try to grab good examples and tag them, and notice what's happening.

"Into that red book" (preposition demonstrative feminine accusative singular)
"With those small buildings" (preposition neuter demonstrative instrumental plural)
"I see these mayors" ( animate-accusative,pronoun, masculine, plural)

Basically, anything that's weird compared to english, grammatically basic and important, and that will be used regularly in the language.
Also, I tag for connectors, or common turns of phrase, which don't translate word for word:
"the thing is..", "be that as it may", "actually, i don't know"

I don't even review them that much : ) I find just making a point of noticing a good example and tagging it helps.

I like to tag into categories like food, family, travel, slang, etc. These help me mentally categorize words and also give me a decent hint (that isn't the answer) when I review.

I agree with maths that often the act of tagging is in itself useful because it helps us notice. I do find review tagged lists of different cases is helpful because we become more attentive patterns. Cases are my main tags in Russian.

Is anyone having trouble creating Tags. If so could you describe your set up and the problem.

I've just started creating tags and I found it very helpful! I started to tag in Turkish similar structural patterns, verb moods and tenses and yes, in fact even starting to notice these things helps a lot! And whenever you feel like it you can go to the "LingQs" tab and display the patterns you'd like to revise. So much helpful!

Wouldn't it be possible to display tags on the flashcards while doing daily reviews? That would also help noticing things - like for example noticing that I didn't tag a certain verb for being reflexive, because at the time of creating that lingq I had no idea of such verbs. It's too time-consuming to browse through hundreds or thousands of lingqs to find a certain pattern to tag it.

We're looking to keep the flashcards in their current form for now. When you go to study flashcards from a LingQs of the Day email, all the words in the session will be listed on the page as well. Using this list would probably be the best way to add tags to the words you are in the process of reviewing.

However, this is a good idea, one that Vera, I believe, has suggested before. It is something I would like to see and depending on how things develop it might be something we do in the future. We have a long list.

Yes, I suggested long time ago to show the tags on the flashcards because I always tag my words. It would be great to have the tags on the flashcards.

OK, I see. Or in fact I could leave lingqs created in the past as they are, making sure to tag new lingqs correctly. Fortunately, LingQ has now enough languages/features/materials to keep me busy for the next few years, so I don't really need to complain about anything. That was just a small suggestion.