Two possibilities: Still, I should improve my skills. I should still improve my skills. (the adverb should be placed AFTER the first modal verb).

Thanks!

I still should have to improve my verbal communication skills. However, the sentence does not sound natural or fluent adding still makes no difference. "I still have to improve my verbal communication skills" <-- is a more natural (but antiquated ) and a more positive way of saying it "I have to improve my verbal communication skills" <-- correct in modern English and what you should use. Today now I still = a bit ambiguous Should = must have to = must what you have said is = " I (different people understand or translate differently) + Must + must improve my ( --- ). or not fluent and not clearly written

Still, I should improve my verbal communication skills. The idea is to communicate correctly and precisely. When you used 'to' , it refers to your goal. At the same time, you are using should have . So, you are adding complexities to a simple sentence.

I still should have to...