Here is some gearing tips for you, only use Advanced Skill Armoring as well as Advanced Skill Barrel, use Advanced [Color] Hawkeye/Eviscerating Crystal. Mods should be Advanced Artful Mod or Advanced Keen Mod depending on what you need, Enhancements is slightly more tricky, but you should only use the following Advanced Acute Enhancement, Advanced Initiative Enhancement, Advanced Battle Enhancement or Advanced Adept Enhancement.
Make sure to look at the earpiece and implants that you buy, you want the ones with high cunning and lower endurance, it's easy to pick the wrong ones. Important note that might help you gear up is to get the Tionese/Columi/Rakata Shells (the item) and then place your armorings/mods/enhancement into these, then you will keep the setbonus that is very good for snipers. Regarding Operations, I would say to continue with EC Story Mode and TFB Story Mode as well as KP HM/EV HM to get many black hole commendations, if possible, do dailies on Section X as well as Black Hole at least once a week to get the weekly done (gives black hole).
What you you should buy:
Black Hole Trapper's MK-1 Device - Crit + Surge
Black Hole Targeter's MK-1 Enhancer - Acc + Crit
Black Hole Trapper's MK-1 Gloves - Best Armoring, Power Mod, Power + Surge Enhancement
Black Hole Trapper's MK-1 Leggings - Best Armoring, Crit Mod, Crit + Surge Enhancement
Black Hole Mender's MK-1 Boots - Best Armoring, Power Mod, Power+Surge Enhancement
Black Hole Trapper's MK-1 Boots - Best armoring, Crit Mod and Acc+Crit Enhancement
First of all, get the earpiece and the implants, these are cheap and you won't need to replace them anytime soon, then focus on getting one of the boots and the gloves, they cost the least amount of blackhole coms and give the best stats. From that point it's a grind to buy the same items again and again depending on what stats you need, rip them out from their blackhole shells and put them into your Tionese/Columi/Rakata gear. Getting the correct armoring in your Chest and Head is the lowest priority, focus on getting the correct mods and enhancement for your gear. If you have Cybertech/Artifice on any of your characters, send the gear that is "over" and you don't need (bad amorings, mods you already have enough of or enhancement with bad stats), RE them and you will get Molecular Stabilizer. With these you can then later on craft (or get crafted for you) armorings, mods and enhancements that you can put in any gear.
As said before, try to find a good guild where you can develop and get better gear from running EC HM or what they might be doing, don't go for the top guilds on your server, pick a guild one step below. It will be a huge grind for you at the start to get the best gear for you sniper, trust me, I have one myself and I spent loads of times getting my gear. You have the advantage of the weeklies that give very good rewards (blackhole coms), make sure to do them every week, try doing daily flashpoint and weekly SM raids for the same reason.
I am aware of the fact that I have brought up loads of information here, so feel free to start asking any questions you might have and I, or someone else will do our best to answer them!