Siman 138 – Do not leave less than 3 pesukim before a gap
If ever you are ending an aliya at a non-indicated place (e.g. leaving the last aliya for acharon) be sure not to end it less than 3 pesukim before a gap whether pesucha or s’tuma. Similarly do not end the aliya less than 3 pesukim after the gap because then the next oleh will need to begin less than 3 pessukim from the gap which is also forbidden. (ShA 1 – MB 2)
If the last aliya consisted of a 5-possuk parsha, the Maftir must repeat all five pesukim, l’chatchila. (MB 2)
You may end an aliya before a parsha with only 2 pesukim since you are ending at a gap. However l’chatchila, you should not end your aliya after a parsha with only 2 pesukim except on Rosh Chodesh when sh’lishi ends after “U’vyom hashabbos…” (Rama 1 – MB 4)
You should always try to begin and end your aliya at a good phrase for Yisroel. Do not end the aliya on a possuk of a bad deed. (Rama 1 – MB 5,6)
Do not call a blind or lame man for the parsha of “Averres oh shavur…”. Nor should you call up someone who is suspect for z’nus for the parsha of arayos, etc. (MB 5)
When reading from the berachos or k’lollos, do not have anyone specific in mind – just read l’shem shomayim. (MB 5)