MB 35: One should pray - And this prayer has no conclusion [it does not end with Boruch Atah Hashem...]. The Taz wrote that the same applies to someone studying on his own, and especially if he has reached the level of answering queries [horoh] he must pray that he should not err in his learning or in his judgement to say "pure [Tohor]" on something that is really impure [Tomeh] or "permissible [Mutar]" on something prohibited [Osur]. It is good to use a small, yet all-inclusive text as follows: "May it be Your Will... that You enlighten my eyes with the light of Your Torah and that You prevent me from falling into any trap or mistake whether in the Laws of Isur Vheter [prohibited vs. permitted], in monetary matters, in judgement [Horoh] or in learning. Open my eyes so that I can perceive wonders from Your Torah. And where I have already erred, put me back on the right track, and do not withhold from my mouth a truthful matter for Hashem gives wisdom, from his mouth knowledge and understanding." When one learns together with others he must also request that he should not be happy [or make fun] with their mistakes and that they should not be happy when he makes a mistake as it says in the Talmud.
MB 36: And upon exiting - The Rambam writes in his commentary on the Mishnah that these two prayers are obligatory. He may pray either sitting or standing, however it works out, and he should not turn his face towards either East or West and he should not bow etc., look there. The Elyah Rabah and other Later Authorities quote him [meaning as the law].
MB 37: He should say: "I thank You etc." - Similarly, someone engaged in Torah study alone all day should say this every evening upon concluding his learning.