1. create non-derived words(roots) and derivational affixes
2. see how natlangs derive words
3. calque compound words and derived words from natlangs, you can calque from Latin, Greek, German, Dutch, Chinese, etc.
Also you can take a look at this:
https://linguifex.com/wiki/Guide:Derivations
For a list of potential non-derived words, you can take a look at the Swadesh list, the Leipzig-Jakarta list, the globish word list(you can find it at
http://www.jpn-globish.com/file/1500motsGlobish.pdf ), the Basic English wordlist(you can find it at
https://simple.wikipedia.org/wiki/Wikip ... d_wordlist ), the list of gismu of Lojban(you can find it at
http://www.lojban.org/publications/wordlists/gismu.txt ).
Something about affixes:
Affixes turning nouns into adjectives seem to tend to mean "of or pertaining to ..."(represented by -ic, -ical, -al in English), "with the characteristic of"(represented by -ish in English), "with, full of or covered with..."(represented by -y, -ful, -some, -ed, -ive, -ous in English), "without or without the property of..."(represented by -less in English), "resembling..."(represented by -like in English), "in the direction of..."(represented by -wards, -wise in English)
Affixes turning verbs into adjectives seem to tend to mean "being the patient of the action"(represented by -ed in English), "doing the action"(represented by English -ing, -ive), "tending to do the action"(represented by English -ive, -ing, -ous), "capable of being the patient of the action"(represented by English -able).
Moreover, don't let aesthetics bother you too much.
Finally, take your time, Rome wasn't built in a day.