Predicting the weather primitively isn't an exact science and below is just rules of thumb and they are not hard and fast.
First things first. You need to know where you are geographically to best access what types of severe weather events are most common in that area. Tornadoes, hurricanes, blizzards.
Time of Day, Time of Year
Thunderstorms and associated tornadoes most often occur from two to six pm and usually during the months from April through June. Towering cumulus clouds spawn tornadoes so be wary if you see an ominous cumulus cloud headed your way during the spring or summer.
On a beautiful clear days, the smoke from a campfire rises steadily. But if it starts to swirling and descends then likely stormy weather is on the way.
Red sky in morning Sailors take warning. Red sky at night sailors delight!
In the morning if the grass is dry, this indicates clouds or strong breezes, which can mean rain. If there's dew, it probably won't rain that day. However, if it rained during the night, this method will not be reliable.
Easterly winds can indicate an approaching storm front, westerly winds just the opposite. Stronger than normal winds indicate high pressure differences, which can be a sign of advancing storm fronts.
The saying "Flowers smell best just before a rain." is true take it to heart and this doesn't just apply to flowers that smell good. Also swamps will release more gases before a storm and that isn't a very pleasant smell.
The hair knows! Your hair might act differently in high humidity. Curls? Could mean approaching rain.
Clouds going in different directions equals bad weather coming, possibly hail.
Cirrus clouds the thin streaky clouds high in the sky that look like they come from a paintbrush or Alto-cumulus clouds the ones that look like a mackerels side usually mean bad weather within the next day or two.
Cumulus towers usually mean brief afternoon thunderstorms. They may not last long but they can be very intense.
Remember this saying. Circle around the moon, rain or snow soon.