You can always cook until tender. Chuck roast is a really popular substitute for brisket. Found a random recipe you can check out.
Use an acidic marinade with vinegar, citrus juice, wine, yogurt, buttermilk, or even Coca-Cola. But I don't ever think a marinade makes a big difference to tenderness. I only marinade when I want to add flavor.
Brine it. Cover the cut with salt, leave in refrigerator overnight, rinse off in the morning.
To me the only way to make a lean cut noticeably tender is hammer it, use a jaccard, or brine it as far as I know. Bigger cuts you can dry age.
On the other end of the process, letting the meat rest for 10 minutes or so after cooking will help. Also, slicing thinly against the grain will help make it seem more tender.