Start to do your own eliquids is not that easy. The basics are somewhat easy to understand but it requires a lot of time and many failed experiences

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You need your bases, nicotine and flavours to make your own juice. As sparkky1 said e-juice me up is the best tool to start understanding the numbers and ratios. A lot of tutorials are out there, just google it. I buy my bases (VG and PG) at pink-mule.com - they have premade bases already with nicotine wich, for me, is easiear and saffer to use.
There are many flavours brands, I use Flavour Art, Perfumers Apprentice and a new Polish brand called LiquidPure. For recipes I advise you to start with simple flavours like 1/2 flavours liquids. There are many recipes around there just google "eliquid recipes" and you will find a new world

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You also need to read info about steeping your juice.