How to tell the difference in these Japanese words/alphabets?

Question:

I learned Hiragana and Katakana in a course. But i'm starting to learn Kanji on my own. I noticed that for example:
千 (Sen=thousand) looks like チ(chi in katakana)
十(jû= ten) looks like ナ (na in katakana)
and finally in katakana ン (n) and ソ (so)

I know they are not exactly the same, the curves are a little different. But i can't tell them apart most of the times.
How do you do it??understanding from the context or you really notice the curves?
Do you have a tip for me to not be confused? Thanks

Answer:

Context
My tip is do not over think or worry about it too much. Katakana are used for foreign words only. And sometimes it can be the italic counterpart in English.
When writing in hand, normally Katakana are written in an italic way so you'll notice the curves right ahead.