Lag Ba'omer Segulos by Rabbanit Yemima Mizrachi:
1. Tehillim 67 (7 times) - It's a psalm of Hod and gratitude
2. It's a day of joy and happiness (always falls out on the same day as Purim)- you cannot be sad today!
3. Ask for children "who will be exactly like Rabbi Shimon"
4. Ask for a home.
5. Chida: Light 17 candles (gematria tov/good) - from Lag Ba'omer to Shavuous there are 17 days and we ask Hashem for good days, days during which we earn receiving the Torah."
6. Rabbi Yehonasan Eybeschutz : Lag Ba'omer is when you should repent from the biggest transgression of your life, and Rabbi Shimon will intercede on your behalf in heaven.
From Rav Schwartz: see Bilvavi.net: