One easiest secret of speaking Japanese naturally - Omit particles. - 超簡単！ 日本語の自然な話し方
Do you want to speak Japanese naturally? And you don't want to study much? Then I'll show you the way. The easiest and effective way is "when you speak, you don't say 'particles'", such as '～が', '～は', '～の', '～に', '～で', '～へ'.
I recommend it because I do it every day as a native Japanese speaker. For example, when i talk with friends, i say
"このあいだ北海道（ほっかいどう）いったけど、スシ（SUSHI)、めちゃくちゃうまかったわ～。北海道、魚（さかな）美味（うま）いし（Lately I went to Hokkaido, and sushi was great there! Hokkaido has lots of delicious fishes there"、
or "きのう、映画（えいが）いったけど、超（ちょう）おもしろかった( I went out to watch a movie, and that was awesome) "。
I say no perticles there, .but these lines,of course, completely make sense and i can keep the conversation rolling.
Well, when i correct foreigners' Japanese writings there in the notebook https://www.italki.com/notebooks/japanese
, I never omit perticles, because it's after all written language. Simply, i don't omit perticles when I write, i do when I speak.
Maybe now you are afraid like 'Does'nt that sound impolite?'. OK, i understand your fear. Then you should speak "このあいだ、北海道、いきました。スシ、とても、おいしかったです"slowly, clearly, honestly with a calm and descent expression on your face like ladies and getlemen. Then no problem. I think this works universally.
I'm sure this is the easist way for you because it's about omitting, not about adding. Then start today!
P.S: Sorry, let me tell you one exception. It's '～と' which means 'with'. When you want to say 'I want to eat with you', you never ever say 'わたし、あなた、食べたい', which means 'I want to eat you'. Instead you say 'わたし、あなたと、たべたい'。