Re: istikhara..
KKF is right; all you have to do is pray 2 rakat nafl and then recite the dua for istikhaara (if you don’t know it, just google or ask in here). since it’s just ibaadat after all, there is of course no limit to how many times you can do it, but inshaAllah after doing istikhaara you will feel an inclination one way or the other.