It depends. There are roughly 4 types of economists that I have seen in my 20 year career.
1. De facto economists. These are people who are called economists because that is their job title. They might know a bit of Excel and a bit of Freakanomics. They usually have an undergrad in economics (though often not) and some have masters level education ( more important as the market for economists heats up). They mostly make graphs, tell what these graphs say, and use an amateur level of common sense in their work. I have seen them in alot of government agencies, engineering firms, international organizations, think tanks and especially banks. Development organizations also "make" them (and they mix economics words and concepts with generalities and jargon unique to their industry. Many work for the media (and write articles, blog, podcast and so forth. They make up the vast share of the "profession" (in quotes because PhD economists would not consider them as peers.
2. Trained economists. They are people who have specific training in economics. They know enough about theory, regressions and econometrics to really be dangerous. Many will have PhDs. They will do most of the regression and statistical work. Much of their writing is for internal use only, and often politely accepted (and then ignored). Many will draft more authoritative sounding briefs, internal memos and will often advise their colleages (de facto economists usually do not). They usually do alot less Excel and graph making, and will focus their time on SPSS (or similar econometric software). They may also spend time publishing policy and "practitioner" briefs (though many have not had what a businessperson would consider a "real" job). They usually don't spend alot of time writing academic papers, and spend a lot of time with other economists. They haunt the policy institutes and think tanks, as well as the development organizations and even some universities.
3. Academic economists. These get most of the attenion. They will build mathematical models , test them with data, and usually live or die by their publications. They usually do not interact with business (though some do). They are basically what you think of as an economist. A PhD is as necessary to them and passing the bar is to the legal peofession. A good share of them will spend a lot of time engaged in theoretical maths. Thats all they do. They go to conferences, debate equations and do the usual stuff. No model, no job. In later life, many try their hand at business (as consultants and advisors while still employed by their university). Some will leave academia for more policy or commerically oriented work.
4. Guru economist. They are a rare breed that usually jump from business to government to academia. They may use the skills of a de facto economist in a rush on a work assignment (and keep their language as simple as possible). They will the n switch to academic, where they do the stuff academic economists do. Their portfolio work/job means they could be doing practically anything....from penning an article for a newspaper to speaking on any topic know to mankind "from the economists' perspective"). You basically already know who these people are. They give fancy speeches and go to Davos (or their local equivalent for guru-itos).
Of course, there are a million exceptions that prove the rule. Some academics will be historians or even anthropologically-minded. They make rigorous arguments, without so much math. The de facto economist may see his or her day in the sun as a guru (depending on politics, their assignment, etc.).
Usually though, and most importantly, they do what they want or think is best. Because economics has no certification board, standard protocols of practice or often measurable results, many economists do what they can or want. Many bosses do not understand what economists do (except talk about inflation, unemployment and maybe the prices of stuff). The title is flexible enough to cover most areas of human activity (as economists even give advice on love while 'thinking as an economist').
Email me if you want to know more...and hope this helped!