Starting sentences confidently (zelfverzekerd zinnen beginnen) is one of the markers of fluency. In English you use well, so, I think, basically — Dutch has equivalent openers. Conversation starters: Trouwens… (By the way…), Overigens… (Incidentally… — more formal), Sowieso… (Anyway…), Hoe dan ook… (Anyway / however that may be…), Dat gezegd hebbende… (That said…), Stel je voor… (Imagine…), Wist je dat…? (Did you know that…?).
Opinion openers: Naar mijn mening… (In my opinion…), Ik vind dat… (I think that…), Persoonlijk denk ik… (Personally I think…), Wat mij betreft… (As far as I am concerned…), Ik sta er zo in… (My position on this is…), Vanuit mijn perspectief… (From my perspective…), Eerlijk gezegd… (Honestly speaking…). These openers signal you are about to give a personal view and frame your statement accordingly.
Concession and contrast starters: Aan de ene kant… (On the one hand…), Aan de andere kant… (On the other hand…), Hoewel… (Although…), Toch… (Yet / still…), Desondanks… (Despite this…), Dat neemt niet weg dat… (That does not change the fact that…), Afgezien daarvan… (Apart from that…). Mastering these starters lets you structure complex thoughts in Dutch from the very opening of your sentence.