How to block ads while using Mozilla Firefox

You can easily manage the ads in Mozilla Firefox using 'Adblock plus 2.0' . For disable the ads on Firefox we should go to filter preferences option on Adblock plus. There is a menu called "Allow non-intrusive advertising" and we need to uncheck this one.

You can change this option whenever you want by simply check the icon and the ad you want will appear automatically.

AdwCleaner is anther famous tool used in Mozilla Firefox for removing unwanted advertisements.

AdBlock Plus
This is the best ever method you can use for blocking ads on Firefox. You can configure it to block all ads across all websites, or decide to allow a few of them.
The other two good options for the purpose include NoScript and FlashBlock . You can whitelist specific websites to allow ads on them.

Almost every adblock plus add-on out there is compromising with the advertisers. Now they have thing called safe list which by default allows some advertisers to stuff the cookie into the browser. Also you can see those ads sneaking into the page.

You have options like -

Ghostery
Adblock
Adblock Plus
NoScript
uBlock
Trackblock Plus

Search for these addons on Firefox addon page. I prefer two of the below addons.

Adblock - This addon recently announced that they are allowing some advertisers to show in safelist. They have taken this decision due to lack of revenues for developing the addon.

Ad block plus - This addon went to safelist option during 2013. And now they also display some ads on random page.

Make sure to use either Adblockplus or Adblock along with NoScript (custom settings). Also subscribe to Fatboy list or similar strict list for advertiser filters.

I personally suggest you to avoid Ghostery. This app itself stores a lot of content which later is being sold to advertisers to compensate for the ads not being shown.