Ohh, yeah, that can be a bit tough if you don't know exactly how to do it. While posting a few sentences/paragraphs here might be helpful, here are a few pointers that I use:
1) group ideas - if you're doing descriptions especially, go in a sequential order, from biggest to smallest detail. Don't jump around from descibing, say, how crowded a bar is to the nice glasses to the tables. Go from the bar to the tables, then to the glasses.
2) repeating words - Don't use the same word to start many sentences or paragraphs. I, personally, try never to start more than 2 sentences with the same word.
3) smaller paragraphs - If you have a long area of description or movement, break them up into a few smaller paragraphs. I don't know about others, but I find it a lot easier to read and follow then there are 2 smaller paragraphs instead of 1.
These aren't all, probably, and i might be wrong on some, i'm still learning too
Hoped this helped though