Tips on what?
That's a pretty broad question. Tips on growing marijuana in general? Well we could all write a book on that from type of grow mediums to the lights, to environment to pheno types from when to harvest how log to veg what training if any you are going to do type of Nutes you will use, feeding schedule. The list goes on and on.
We would also need the information on exactly what you are using right now to tell you what you need to improve on.
But by the way, the age of your plants looks roughly week 3 maybe 4 of veg.