Desert Dragon;
Good advice has been given...the best, imo is flrst to obtain a good reloading manual...what brand really doesn't matter. They are all good.
Then follow its recommendations.
My brother-in-law and I settled on what we call "hot .38
Special" or "mild magnum" loads, me for my model 19, and him for his Blackhawk.
When I shot IPSIC, my standard load was 5.5gr. Unique, 357 brass, standard prlmer, 150-162 gr cast SWC, medium crimp, which gave 860 fps chronogrphed from my 4' barrel. Didn't make major, but, if I shot well enough, no handicap. The only problem was it rarely wouldn't knock down the poppers.
Nowadays, I have settled on loads that approximate the famed "Miami-Dade County", "RCMP", or" FBI" loads, which have approximately the velocity of 38 special +P loads...950-1000fps. This can be achieved (Don't have a chronograph), by ~ 5.2 gr Hodgdon Universal,(Not fave, but I am miserly, and won't throw it away!
5.9 gr. Unique, or 10.5 gr. 2400, for all my shooting, which includes 125-135gr. SJHP or plated, up through cast or swaged 150-158-162gr bullets, which all provide acceptable accuracy, enjoyable shooting, and reasonable velocity.
I have always liked 4756 powder, but I quit using it about Speer Manual #10, when they warned about fluctuations in pressure. Now, I find that some fellows have been using it in loads, with good velocity and no excess pressures. I ran out of another of my favorite cast bullet powders, Blue Dot, about the time they published their warning , and just never bought any more, although the latest data seems to have addressed the problem. I may give it another go.
Anyhow, read your manual, pick a powder, shoot it. You don't like, get another. That's the fun of our frustrating and fascinating pastime. ENJOY!