Tip #1 - Catchy Titles
Having a catchy, memorable title is a great way to keep the name of your song stuck in your listeners' heads, so they'll know what it's called when they go to search for it later. That's why using alliteration, rhyme, and a flowing, consistent rhythm in your song's title can be a great way to keep it memorable.
Tip #2 - Singing Rhymes
One thing to consider when choosing a rhyme, or a word at the end of a line, is whether or not it ends with a hard consonant sound. Words that end with vowel sounds will be much easier to sing, if the note on the last word is held out.
Tip #3 - Using Line Lengths for Contrast
Contrast between the different sections of your song is important to keep your song interesting throughout the whole track. A great way to achieve contrast from your verse to your chorus is to use different line lengths in each section. Very short melodic (and lyrical) lines in your verses will contrast well against longer lines in your chorus, and vice versa.
Tip #4 - Scales for Melodies
Using the scale of your song's key is a great place to start if you're stuck with coming up with a melody. Aside from using the notes in the scale of your song's key to write a motif, you can also use the pentatonic and blues scales to come up with melodies as well. You can write melodies with the major pentatonic and blues scales if your song's in a major key, while the minor pentatonic and blues scales can be used to write melodies if your song's in a major or minor key. They're great tools to try, if you're having trouble coming up with a melody off the top of your head.