I have a heretical philosophy when it comes to e-juice. Most everyone will tell you this juice is better than that juice, and the next person will swear just the opposite. The bottom line is most juice from a reputable company is the same. There may be differences in the extreme upper & lower tiers, but by and large the juices from the mid tier (translate to affordable) companies are comparable.
My recommendation is to search the sites for companies that offer a wide selection of flavors, the ability to adjust VG/PG ratios, Nic levels that suit you, and maybe the ability to "customize" your juice. My personal favorite is Mt. Baker Vapor for all of the listed reasons and they have GREAT customer service. There are quite a few companies that may fit the bill, I would suggest finding a few that piqué your interest and come back to this forum and ask for input ..... many of the companies have dedicated threads that discuss flavors and the general customer satisfaction with the company.
You will find a large & vocal group on ECF touting small "specialty" juice makers with limited flavor selection, while as a rule most of these companies are excellent, I would advise not using them while you are new ... at least not until you develop a "flavor profile". For instance (In my opinion) Nicoticket does the best vanilla flavors out there, but their overall selection is limited, so I wouldn't even attempt ordering from them until you know you like a vanilla vape (they have other flavors too, I'm just using vanilla as an example).
There are companies who's specialty are tobacco flavors ... some specialize in exotic flavors etc etc etc. But my recommendation is start with a company with a wide selection .... two examples are;
Best E Cigarette | Buy Electronic Cigarettes | E Cig Juice - MT Baker Vapor
ECBlend E-Liquids - Something Better
I'm sure there are more