I admit that not all sentences in a phrasebook are helpful for me. Most of the time, I only skim the book to learn sentences that are useful for me. When I'm lucky, I'll find many valuable sentences. Otherwise, those books won't be helpful and would likely be kept on my bookshelf for a long time.
To tackle this problem, I started to make my own phrasebook where I write only sentences that I think are helpful and important in my life. However, it is not easy especially when I'm not familiar with the grammar but luckily, there are online translators to use. I use Google Translate most of the time, although I'm aware of other translators, like DeepL and Bing Translator. So far, I think Google Translate offers the most languages.
Many people say that translators are not reliable, and they are true although not entirely true. I see the translation quality having been improved day by day, and I believe, eventually the result would be as close to natural speech as possible. Right now the translators lack emotion because they don't know the culture in which the language is spoken. For example, Indonesian people always refer to the formal "you" as "Bapak/ Ibu" instead of "Anda" in real-life conversation but translators always translate it as the latter.
If you can get someone to help you make your own phrasebook, that's perfect! However, the reality isn't always as beautiful as it seems to be. I found it difficult to find someone who would spare time and effort to help me make a phrasebook. Thus, my alternative way is using online translators. After the sentences are translated, I would use my limited knowledge to proofread the translation. It might not give a perfect result, but at least, I would say the translation are acceptable for daily informal conversation. The trick to avoiding wrong translations is giving the translators simple and direct sentences. There are no cultural aspects being considered here as there won't be a context, so being simple and direct is recommended.
Below is my multilingual phrasebook. The languages shown below are languages that I already know and languages that I am learning. More languages will be added in the future.