I would give the following advice for noobs in DIY:
Read/search, read/search and read/search some more when you're done reading/searching!
Second, finding out how to mix is easy with various guides, calculators and such, but before throwing a bunch of flavors together in a mix that sounds nice, then imho you need to have tried each and every flavor by itself standalone, so as you know exactly what that flavor brings to the table, and how strong it is.
Also, I would really recommend trying also pg by itself unflavored, and then vg by itself unflavored(I prefer adding 20% demineralized/distilled water to max-vg mixes), so as to also know how exactly these two compounds will influence the final taste of a mix.
Finally, imho, then water is great to both bring out the flavor more, get better wicking, get more effecient evaporation through the lowered boiling-point and finally maximizing coil/wick longevity. With pg add 10% and 20% with max-vg is my recommendation.
Personally I have been DIY'ing for about a year or so, but have recently getting to be really happy about unflavored vg with 20% water, so nowadays that is the only vape I ever make...
Also, for me, then I found out by trying everything seperate, that i actually hate the taste of pg, and actually find it's metallic, alchoholic dry taste to be sweeter than vg, though i'm not allergic or anything. PG however, does wonders for brightening fruit flavor up imho...
Also vg to me has a musty earthy slightly sweet kinda taste to it that I have come to really appreciate...