I don't know whether it's just me, but I think that many Indonesian words look very similar. Are their any ways to memorize them (i.e tips and strategies) or tools to help me?
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Just like in English, memorize only the root words. The trick is to recognize prefix and suffix patterns, because unlike English the Indonesian language uses a lot of prefixes too, not just suffixes. Some words even have both prefix and suffix (confixes)! Here is a comprehensive article explaining the meaning of all common prefixes, suffixes, confixes, infixes, and combining forms: Forming Indonesian Words & Using Indonesian Affixes.
Once you learn how to recognize root words and how to modify root words, you can then focus on memorizing root words only, using common word list such as this list of top 2000+ words, the book Indonesian Vocabulary for English Speakers containing 3,000 common words organized in 101 topics, and other lists you may find from this answer.