If you find any of this helpful be sure too checkout my youtube channel where I post full Swain Gameplay.
Youtube.com/Trapperzimdone

Otherwise, Swain is a character that easily excels at farming in the early game, and also can poke very good if u get a combo off. I recommend using your Q too poke, and your Q + W too farm the minion wave if its pushing into your tower. If you think you have good wave management you can use your full combo too poke if you have good vision and know what your are doing with the wave.

Know your damage. Experiment early game what a full combo does and try too all in at level 6 if you can. Get too know your items too. You are learning you are going too make mistakes and can ask me questions anytime.

Know your healing. Iv'e been pinged many times by teammates that the enemy jungler is coming. Yes, I have eyes and can see him. If you are facing a tank top laner that does no damage too you, go right ahead and kill the enemy jungler when he ganks your lane.

Know your cooldowns. Stopwatch is a broken item. Look at the enemy champions items and he may get that stopwatch at 7 minutes due too his runes. NEVER... Push the enemy wave with no vision near u with your full combo and ult. Cause when you finish the wave, people are going too appear and you are going too have no abilities too use besides the shop key

Know your limits. Yes, there are times when you can run into the enemy team and tank all five people. The videos on my Youtube showcase that. Otherwise of that being very fun, you can not always do that. You can also use your kit too peel, and either too follow up onto a pick your support or other teammate got.

Know your LP. Go gain some, and let me know how this worked out for you...