Unless you're a celebrity, Twitter etiquette is that when someone follows you, you usually follow them back, though this is not firmly established, so don't get offended if they don't.
This last two steps are important, because here's what makes a tweet powerful:
The number of followers that person has
The number of times it gets retweeted
The number of times it gets favorited (to a lesser extent)
You only get followers by starting small and building a network, and you only get retweets if you have followers that like what you have to say.
What's the etiquette for using hashtags and twitter handles? Hashtags are topics, indicated by using a "#". Hashtags can be used in sentences or at the end when it's relevant, for example:
More storage progress: Tesla says it will double capacity of home battery buff.ly/1dwAsp6#climate#solar
Pls RT: Sign up for Congressional #Climate Message Day, June 22, so we can price carbon. buff.ly/1KZstPx
A twitter handle is a person or organization's account, for example, "citizensclimate". You can tweet directly to another account to make sure they see it by using the "@". When tweeting to another twitterhandle, you can put the twitter handle wherever it makes sense, usually at the beginning of the tweet or in context, for example:
@JayFaison1: Thx for stepping up on #ClimateChange! Have you seen @CitizensClimate's market-based solution? youtu.be/9oyguP4nLv0
CCL mentor @samdaleyharris talks citizen empowerment on@Thom_Hartmannyoutu.be/DLquJAQGots #climate via @YouTube
What hashtags (topics starting with "#") should I use?
CCL regularly uses
Other popular ones
Or something else!
If it's the topic of the tweet, just put a # in front of it. Sometimes a topic catches and just becomes popular e.g. #bringbackourgirls, #blacklivesmatter
How do I shorten a link so it fits in my tweet?
If you're tweeting from an app, some apps do this automatically for you. But if not, Bitly is a popular link-shortening website.
If you start your tweet with their Twitter handle, put a period in front of the handle so your tweet will be seen by others and possibly retweeted. If you use #climate, people who follow that hashtag will see your tweet and possibly retweet.
If you want an active twitter network, you'll have to build it. Tweet regularly. Put your twitter handle on business cards, Facebook, Google+, wherever. The modern day is one where everyone must self-promote.
But if you don't want an active twitter network, that's okay too. You can still serve the cause.
Follow persons of interest to stay informed
Tweet directly to them about a topic they just tweeted when you want to be heard
It's a social platform, so the more voices we have, the better we sound. In a chorus, we sound strong.