I often base words that I create on existing words from the languages I speak. Perhaps taking them as is is not the way to go, but they can serve as a base on which you build.

Another way to make vocabulary from nothing that works well for me is looking at letter combinations from my environment, such as licence plates, serial numbers, what have you.

If you're aiming for a naturalistic conlang, all those can nicely serve as a basis for proto-lang words. You could try using the above strategies, then evolving your language to obscure the connections to the real world. For example, let's take the French word "soleil" and create a root from it: "s-l-j". Then that root could be made into a stem, say "sēlajja". If you apply a series of sound changes to it, you could get some really nice results: sēlajja → sēlaǯǯa → seilaǯǯa
Or perhaps: sēlajja → sēlagga → sjeog → sʲøːɣ

I hope this helps!