Tweeples will tell you either how fantastic or fickle Twitter can be - sometimes both. Getting the most out of the service isn't difficult and you can start by culling any spam from your feed and avoiding it in the future.
Don't Be Followed by Spammers
Following thousands, speaking in keywords and sporting no followers (except maybe one or two other spammers); it's quite easy to spot Twitter spammers. Look out for the automatically generated usernames which are often used. For example, "A1C2eQQQ is now following you on Twitter". Make sure to block these types of accounts as soon as possible so they cannot follow you.
Being followed by one of these accounts doesn't mean you'll be seeing their messages, but you don't want to be retweeted by them or be seen in anyway as an easy target for other spam account holders.
Never retweet a spam message or even tweet the name of a supposed spammer, even in jest - this just makes you easier to find.
Avoid Bad Programs and Money Making Schemes
Make sure you take every step to avoid Twitter spam or malevolent attention. It is important that you never give your Twitter username out on questionable third-party sites. You may be tempted by the 'triple your followers' promise, but doing so will inevitably land you on a list of targets.
Don't use auto-follow bots or any other automated programs. An automated email to new followers can be effective in greeting the masses, but Twitter is all about transparency and real conversations. Leave auto-responders to the spammers.
Websites such as Retweet.it promise you more followers, and may deliver, but the value of your tweets will be watered down and your audience may not appreciate your influence and 'unfollow' you.
Choose your Twitter tools carefully. There are many programs and services out there, but some hold more water than others. Here are some handy tools to simplify your life:
TweetDeck - Twitter browser, compatible with Linux, Mac and Windows.
Twhirl - Desktop client which uses the Adobe AIR platform, compatible with Mac and Windows.
TwitterFeed - Made to feed blog posts via RSS into Twitter. Very handy for frequent bloggers.
TwitterFox - A Firefox add-on with popup notifications.