I would start by counting up the most important tags for regular blogging. Are there other tags you think you might need? Then look at less-used tags to see where you might condense or trim some. Single-use tags would be good to weed out.

Also, check your account type. Free gets you 1000 tags, paid 1500, and premium 2000. If you're not already at premium and can afford to upgrade, that's an option.