Hmmm... lots of variables a play here - the juice, the tank, and your tongue.
Pretty much all vapers go through a dull taste period as their taste buds regenerate and adjust to life without smoke (thus the question about your smoking habits above). That will sort itself out (if you don't smoke further) and the best advice is to drink plenty of water. More than plenty, in fact. Imagine yourself having run a marathon in the Mojave desert. You'd need a lot of water, no? Well, drink that, and when you have, drink another glass.
Your tank will degrade with use. Specifically, the coil unit in your tank will gum up or get coated in scorched juice. Not sure if you're using cartomizers, but it happens to them, too. Either way, the coils are disposable. Dispose them regularly (or clean them, but that is probably a topic for another day).
You might also want to invest in a reputable tank if you don't have one already. Given that you mention juices tasting better in a shop than at home suggests you might want to change your current gear. The two most popular clearomizer tanks would be the Protank family and the Aspire family. Many choices within each family; all have devout followings on this forum.
The juice... well, that is going to be the most subjective thing in the mix. What works for you will be just that - what works for you. Vaping will most likely evolve for you over time as your body adjusts to it and you experiment. For where you are now (i.e., your current dissatisfaction with flavor), I'd suggest you go for some stronger juice flavors to get you over this hump. Menthol, licorice, mint, many of the "cake" varieties are all usually quite strong. You might think they're awful sounding but you'll be surprised at how some things will do it for you. I never smoked menthol cigarettes (couldn't stand them), but I like a nice menthol vape. Black licorice candy makes me gag, but I love a good absinthe vape.
In any event, stay strong. You're in the valley of disillusionment - perfectly normal. It will pass, and this forum will help you out with that. When you get over this hump, you'll be made in the shade... and well hydrated... definitely well hydrated.
tl;dr: get a good tank, change coils, drink lots of water, try strong flavors, know you have friends to help here.
