Thanks for stopping by the Illustration Forum.
I use markers all the time, though not the pigmented ones youre talking about. To my knowledge there really isn't any thing else you can do.
All of them run out quickly and most do have a rather foul oder. If you are doing a lot of this you will have to keep several of each color on hand so you don't run out in the middle of a project. I usually keep 3 or 4 each of my most used colors and average around 200 - 300 total in my collection at any one time.
I assume when you talk about streaking you mean how each stroke layed down on a support is visible with markers. In other words they don't blend well. I think the nature of the medium is such that you can't. Markers are a linear medium, they make lines, trying to hide that is difficult at best and not worth the effort, IMO.
What I have done is adapt my style to those constraints. I try and celebrate the individual lines, make them a part of the image.
There are two things that I can think of though that you might try. Again I assume you are trying to fill in a large area with a single flat blended color?
One - you could switch supports. An extremely absorbant support, like rice paper, would allow you to bleed the color over large areas. But you would suffer trying to make detail marks then.
Two - take the marker apart and use the felt inside to make broad strokes. Messy and expensive as this would destroy the marker. Although you're talking about pigmented paint markers and I'm not sure they have a felt in them.
Oh - one other thing - I have seen some markers that you are supposed to be able to fill with your own mediums but the nibs are not that large.
ok so now I'm up to four things you can try ...... as I said before you could try adapting your style to the marker....perhaps with crosshatching.
Hope this helps.
Can you show us a pic of what you are trying to do? And I have to ask why are you trying to do this on canvas? That's one of the last places I would think to use markers. Not that thats wrong at all, you've just made me curious is all.