If you want to be visible in today’s marketplace, you absolutely must have a presence on social media.

But there are so many from which to choose nowadays! In addition to the biggies like Facebook and Twitter, we have lots of newcomers, including Instagram, Pinterest and Tumblr. Additionally, some of the older platforms have undergone major changes in recent months, which affect how effective they are for different functions.

How to know which platforms will best meet your needs?

I asked Alex Hinojosa, our vice president for media operations at EMSI Public Relations, to share some tips for helping you decide.

First, he says, if you plan to handle your social media marketing yourself, try different platforms and use ones with features you enjoy. That will help ensure you stick with it, and may lead you to create inspired content that’s more likely to be shared.

Be on at least two platforms, he says. (If one’s mostly personal stuff for family and friends, it doesn’t count!)

Here’s Alex’s rundown on the advantages and disadvantages of the four most popular platforms:

• Facebook: This works best if you’re an individual interacting on a personal level, as opposed to a business. Artists, authors, public speakers and certain other professionals may benefit from having potential customers get to know them on a more personal basis.

A downside to Facebook is that, in an effort to make money for shareholders, it has begun requiring users to pay for the potentially unlimited visibility that used to be free.

• Twitter: Posts are limited to 140 characters – about the length of a headline – and can include a photo or link to a website. This is a great network for getting to know people without sharing a lot of personal information. Plus, you can follow whomever you want, and anyone can follow you.

“It allows you to easily connect with prospects and potential associates, so it’s great for businesses,” Alex says. “People use it primarily as a source of news, which makes it easy to interact with people you don’t know – you have something to talk about.”

Twitter is now aggressively cleaning house of “robot” followers – dummy accounts sold for cheap that make it look like the buyer has a huge following. Even if you don’t buy robots, you may end up with some as followers.

“Don’t buy followers and delete any of your followers that don’t appear real. Twitter limits how many followers you can have, so you don’t want to waste them on ‘bots,” Alex says.

• LinkedIn: The social network for professionals is a good place to find and meet people within and outside your industry. People can easily see your credentials and endorse your skills. The background information on your profile page – where you went to school, other companies you’ve been associated with – provides great fodder for finding common ground with strangers and building relationships.

• Google+: The Google search engine favors anything posted on Google+, which is great for SEO. It also combines the best features of Facebook and Twitter, including photo sharing and categorizing content using hashtags (#).

“Right now, Google+ can be anything you want it to be,” Alex says. “It’s still new, just more than 2 years old, so it’s still defining itself. I think it will be the next social networking giant.”

As Alex suggests, if you plan to handle your social media marketing yourself, take into consideration the modes of networking that you enjoy along with the best platforms to meet your needs.

If you have limited experience in social media, jump into the platforms that seem to best align with your goals. You’ll have a learning curve, but a little practice goes a long way. And you’ll soon wonder why you didn’t get more involved a long time ago!

Marsha Friedman is CEO of EMSI Public Relations, a national firm that provides PR strategy and publicity services to businesses, professional firms, entertainers and authors. Marsha is the author of Celebritize Yourself and can also be heard weekly on her Blog Talk Radio Show, The PR Insider.