hi chloemarie,i remove snakes professionally and part of my job is i do quotes and give advice on snakeproofing yards,and with out seeing your yard and the exact species that come into your yard its going to be hard to give you complete advice ,but i can tell you lots of people will tell you what DOESNT work ridiculous things like mothballs crushed up ***? and those stupid snake repellers.
It comes down mainly to common sense creating barriers which keep out terrestrial snakes like browns but if there not done properly snakes can wander in where you didnt expect and get trapped in your yard from the barriers.there not going to stop pythons though but really there harmless so not a priority.
By far the most effective way of protecting small dogs is to train them NOT to attack wildlife,which is very possible as dogs respond so well to conditioning techniques.
The only other alternative is to move somewhere with no snakes,i know peolple who have done this.
Spot on except for jack russell's. Well ours anyway hahaha.