In one sentence, describe what the following article is about:

Since you'll use spaces to differentiate between hashtags, all of the words in your hashtags will be clumped together. The same logic applies to punctuation, so never use any apostrophes, dashes, or underscores. For example, the hashtagged version of the phrase "I like trains" would read #iliketrains. The longer your hashtag is, the less likely it is to be discovered. Posting a picture of an old phone with the hashtag "#iphone8" or something similarly misleading may be humorous, but it can also get your account suspended for spam. Most social media accounts have a list of currently trending hashtags displayed somewhere on the home page (Twitter, for example, displays trending hashtags on the left side of the home page on the desktop site), though you can also use hashtags from product ads or follow your friends' examples. Depending on the social media account, the metric for "too much" will vary (Instagram hovers at around 30 per post, while Twitter should only contain a few). If your post is 90 percent hashtag, there's very little room left for substantive commentary--which, after all, is the point of hashtagging.

Summary:
Don't use spaces or punctuation in hashtags. Keep your hashtags short. Make sure your hashtags are relevant. Use pre-existing hashtags. Try not to use too many hashtags in one post.