Reddit reviews The Conlanger's Lexipedia

To Construct a Language: http://www.lulu.com/shop/dan-gaynes/to-construct-a-language/paperback/product-23167868.html

https://www.amazon.com/Art-Language-Invention-Horse-Lords-World-Building/dp/0143126466

https://www.amazon.com/Language-Construction-Kit-Mark-Rosenfelder/dp/098447000X

https://www.amazon.com/Advanced-Language-Construction-Mark-Rosenfelder-ebook/dp/B008XTOV8C

https://www.amazon.com/Conlangers-Lexipedia-Mark-Rosenfelder/dp/1493733001

There are also lots of conlang books at Lulu: https://www.lulu.com/shop/search.ep?keyWords=conlang&type=

Gonna repost my reply to a similar question in last weeks SQ thread:

If you have some cash to spare, I hightly recommend getting the Conlanger's Lexipedia, which goes into all sorts of details about creating vocabulary.

Other than that, there is a lot of creativity that goes into it. Thinking about the etymological histories of your words can help create more real vocab. As a cheap example from my own language, the words for "tea" "to boil" and "culinary/medicinal pine needles" are all related. Derivations are another useful strategy. Rather than just making a new root for a word you come across, ask yourself if you can derive it from a root you already have. Maybe "puppy" is just the diminutive of "dog", "table" might be derived from the word for "to eat".

And that's another thing to think about, the semantic space. In English, desk and table are separate words, but maybe in your language they're the same. Think about your people and what's important to them. A seafaring people living on a chain of tropical islands may have many different roots for types of marine life and nautical terminology. But a desert people may only have one term for "fish" that covers all marine life - "turtle", "Crab", "shark" "Whale" "trout" etc could all be the same word, possibly only distinguished by some adjective or other adverbial. The conlanger's thesaurus is a good resource to check out to get some ideas about dividing up your semantic space.

Go and buy these three books: The Language Construction Kit, Advanced Language Construction (don't worry, it's not that advanced), and The Conlanger's Lexipedia. And if your conlangs are designed for made-up worlds, then get [The Planet Construction Kit] (https://www.amazon.co.uk/Planet-Construction-Kit-Mark-Rosenfelder/dp/0984470034/ref=pd_bxgy_14_img_3?_encoding=UTF8&psc=1&refRID=W79ND56BKPK8EKXT2VQZ) too. If you want to make cultures that are not European then I'd also suggest The China Construction Kit!

Of all of these I'd suggest that you definitely buy The Language Construction Kit and see how you get on. I'd also suggest buying some grammar books of languages you're interested in, and even go so far as to learn a second language if you don't speak one. Having knowledge of at least one other language will help you a great deal.